Question

Find the area in square centimetres of a triangle whose base and altitude are as under:
(i) base = 18 cm, altitude = 3.5 cm
(ii) base = 8 dm, altitude = 15 cm

Answer 1

We know that the area of a triangle = $\frac{1}{2}\times \mathrm{Base}\times \mathrm{Height}$
(i) Here, base = 18 cm and height = 3.5 cm
∴ Area of the triangle = $\left(\frac{1}{2}\times 18\times 3.5\right)=31.5{\mathrm{cm}}^2$
(ii) Here, base = 8 dm = (8 x 10) cm = 80 cm [Since 1 dm = 10 cm]
and height = 3.5 cm
∴ Area of the triangle = $\left(\frac{1}{2}\times 80\times 15\right)=600{\mathrm{cm}}^2$