1
Perimeter = a + b + c
s=\frac{a+b+c}{2}
Area=\sqrt{s(s-a)(s-b)(s-c)}
2
Perimeter = 3a
Area=\frac{\sqrt{3}}{4}a^2
3
Perimeter = 2a + b
Area=\frac{1}{2}b\sqrt{a^2-\frac{b^2}{4}}
4
Area = ½ × BD × (AX + CY)
5
Area = ½ × AC × BD
6
Perimeter = 2(l + b)
Area = l × b
7
Perimeter = 4a
Area = a²
8
Area = base × perpendicular height
9
Area = ½ × d₁ × d₂
10
Area = ½ × (a + b) × h