(iv) Find out the ratio of the sum and the product of two roots of the equation 7x²−66x + 27 = 0
Answer
Sum of roots (α + β) = 66\over 7
Produt of root (α β) = 27\over 7
Ratio of the sum and the product of two roots
= 66\over 7 : 27\over 7
= 66 : 27
(v) Rationalize the surds of the denominator: \frac{12}{\sqrt{15} - 3}.
Answer
\frac{12}{\sqrt{15} - 3}
=
=
= 2√15 + 3
(vi) The radius of the circle with the center 'O' is 13 cm and a chord AB with the length of 10 cm on it. Calculate the distance of the chord AB from the center of the circle.
Answer
Radius (r) = 13 cm
BM = 10\over 2 = 5 cm
Distance from the centre (OM) : OM² = 13² - 5²
or, OM² = 13² - 5² = 169 - 25 = 144
or, OM = √144 = 12 cm
(vii) AOB is a diameter of a circle whose center is O. The point C lies on the circle. If ∠OBC = 60∘, find the value of .
Answer
Given:
- AOB is a diameter of the circle with center O.
- Point C lies on the circle.
- ∠OBC = 60°.
∠ACB = 90° (angle subtended by a diameter at any point on the circle is a right angle)
Triangle OBC is isosceles (OB = OC, both are radii of the circle)
Since ∠OBC = 60°, we also have ∠OCB = 60°.
∠OCA + ∠OCB + ∠ACB = 180° (The sum of angles in any triangle is 180°)
or, ∠OCA + 150° = 180°.
or, ∠OCA = 180° - 150° = 30°.
(viii) A circle with the center 'O'. A point P is 26 cm away from the center of the circle, and the length of the tangent drawn from the point P to the circle is 10 cm. Calculate the length of the radius of the circle.
Answer
Let the radius of the circle be r.
The line from the center O to the point of tangency T (where the tangent meets the circle) is perpendicular to the tangent line PT at the point of tangency. Thus, we have a right-angled triangle OTP, where:
- OT = r (the radius of the circle),
- PT = 10 cm (the length of the tangent),
- OP = 26 cm (the distance from the point P to the center O).
Using the Pythagorean theorem:
OP² = OT² + PT²
Substitute the known values:
26² = r² + 10²
Simplify the equation:
676 = r² + 100
Now, solve for r²:
r² = 676 - 100 = 576
Finally, take the square root of both sides:
r = √576 = 24 cm
Thus, the length of the radius of the circle is 24 cm.
(ix) DE || BC of Δ where D and E are two points on AB and AC, respectively. If AD = 5 cm, DB = 6 cm, and AE = 7.5 cm, calculate the length of AC.
Answer
Given
- AD = 5 cm
- DB = 6 cm
- AE = 7.5 cm
AB = AD + DB
or, AB = 5 cm + 6 cm
or, AB = 11 cm
(AD / AB) = (AE / AC) [Since DE || BC]
or, (5 / 11) = (7.5 / AC)
or, 5 × AC = 7.5 × 11
or, AC = (7.5 × 11) / 5
or, AC = 82.5 / 5
or, AC = 16.5 cm
(x) If the height of two right circular cylinders is in the ratio of 1 : 2, and the perimeters of the base are in the ratio of 3 : 4, find the ratio of their volumes.
Answer
Given
h1 : h2 = 1 : 2 --- (i)
Perimeters of the base = 3 : 4
C1 : C2 = 3 : 4
or, 2πr1 : 2πr2 = 3 : 4
or, r1 : r2 = 3 : 4 --- (ii)
Ratio of their volumes = V1 : V2
= πr1²h1 : πr2²h2
= r1²h1 : r2²h2
= {r_1}²\over {r_1}² × {h_1}\over {h_2}
= ({3\over 4})² × {1\over 2}
= {9\over 16} × {1\over 2}
= 9 : 32
(xi) If the length of the radius of a sphere is increased by 50%, find how much percent will be increased of its curved surface area.
Answer
(xii) The length of the diagonal of a cube is cm. Calculate the total surface area of the cube.
Answer
Question - 5
At the same rate of simple interest in percent per annum, if a principal becomes the amount of Rs. 7,100 in 7 years and Rs. 6,200 in 4 years, determine the principal and rate of simple interest in percent per annum.
Answer
ii) Three friends have started a business by investing Rs. 8,000, Rs. 10,000, and Rs. 12,000 respectively. They also took an amount as a bank loan. At the end of one year, they made a profit of Rs. 13,400. After paying the annual bank installment of Rs. 5,000, they divided the remaining money of the profit among themselves in the ratio of their capitals. Calculate the profit share of each.
Answer
iii) Calculate the difference between compound interest and simple interest on Rs. 20,000 for 2 years at 5% per annum.
Answer
Question - 6
6. Answer any two questions: [3x2=6]
(i) Solve: <span class="katex"><span class="katex-mathml">\frac{1}{\text{a+b+x}} = \frac{1}{\text{a}} + \frac{1}{\text{b}} + \frac{1}{\text{x}}, x ≠ 0, -(a + b)
Answer
(ii) Form the quadratic equation whose roots are -4 and 3.
Answer
(iii) If m + , then find the value of
(a) m² +
(b) m³ +
Answer
Question - 7
Answer any two questions: [3 × 2 = 6]
(i) Find the simplest value of:
Answer
(ii) If a =
Answer
If 15 farmers can cultivate 18 bighas of land in 5 days, determine by using the theory of variation the number of days required by 10 farmers to cultivate 12 bighas of land.
Answer
Question - 8
(i) If a : b = b : c, prove that
Answer
(ii) If
Answer
Question - 9
Answer any one question: [5]
(i) Prove that the opposite angles of a cyclic quadrilateral are supplementary.
Answer
(ii) Prove that the perpendicular drawn to a chord which is not a diameter, from the center of the circle, bisects the chord.
Answer
Question - 10
(i) ABCD is a cyclic quadrilateral. Chord DE is the external bisector of . Prove that AE (or produced AE) is the external bisector of
Answer
(ii) Two chords, AB and CD of a circle with center O, when produced, intersect each other at the point P. Prove that ∠AOC−∠BOD = 2 × ∠BPC.
Answer
Question - 11
Answer any one question: [5]
(i) Draw a right-angled triangle having two sides 4 cm and 8 cm length respectively. Containing right angle. Then draw the circumcircle of the right-angled triangle. (Only traces of construction are required.)
Answer
(ii) Draw a circle with a radius of 2.6 cm and draw a tangent on this circle from an external point at a distance of 6 cm from the center of the circle.
Answer
Question - 12
Answer any four questions: [4x4=16]
(i) Half of a cuboidal water tank with length of 2.1 m and breadth of 1.5 m is filled with water. If 630 liters of water is poured into the tank, then calculate the increased height of water.
Answer
(ii) The height of a right circular cylinder is twice its radius. If the height would be 6 times its radius, then the volume of the cylinder would be greater by 539 cubic dm. Calculate the height of the cylinder.
Answer
(iii) In a right circular conical tent, 11 persons can stay. For each person, 4 sq. m space in the base and 20 cu.m. air are necessary. Determine the height of the tent put up exactly for 11 persons.
Answer
(iv) Calculate how many spherical marbles with 1 cm radius each may be formed by melting a solid sphere of iron having 8 cm of radius.
Answer
(v) The inner length, breadth, and height of a tea box are 7.5 dm, 6 dm, and 5.4 dm respectively. If the weight of the box filled with tea is 52 kg 350 gm, but in the empty state, its weight is 3.75 kg, then calculate the weight of 1 cubic dm of tea.
Answer
[Alternative Question for Sightless Candidates]
Question - 11
Answer any one question: [5]
i) The lengths of sides containing the right angle of a right-angled triangle are given. Describe the procedure of construction of the circumcircle of the triangle.
Answer
(ii) Describe the process of drawing one tangent to a circle from an external point.
Answer
[Additional Question for External Candidates]
13. (a) Answer any three questions: [2x3=6]
(i) Find the value of aa, if one root of the equation 2x² + ax + 8 = 0 is 1.
Answer
(ii) What is the rate of simple interest per annum, when the interest of some money in 10 years will be \frac{2}{5} part of its amount?
Answer
(iii) Which one of √8, is not a similar surd?
Answer
(iv) Find the total surface area of a cone whose diameter of the base is 20 cm and slant height is 25 cm.
Answer
13. (b) Answer any four questions: [1x4=4]
(i) What will be the compound interest and simple interest for one year at the fixed rate of interest on a fixed sum of money?
Answer
(ii) What is the value of a semicircular angle?
Answer
(iii) Find the third proportional of 5, 10.
Answer
(iv) What is the name of the solid which is composed of only one surface?
Answer
(v) What is the relation between the opposite angles of a cyclic quadrilateral?
Answer