Question

In a triangle, the base is double the height and area is given to be 400 sq cm. Find its base and height.

• A. 10 cm, 20 cm
• B. 20 cm, 10 cm
• C. 40 cm, 20 cm
• D. 20 cm, 40 cm

Answer 1

The correct option is C 40 cm, 20 cm

Let $x$ be the length of height of the triangle, then base of the triangle will be $2x$
Area of a triangle = $\frac{1}{2}\times \text{base}\times \text{height}$
= $\frac{1}{2}$$\times$2$x$$\times$$x$
i.e., 400 = $x^2$
$⟹x=\pm 20cm$
Since length cannot be negative we have $x=20cm$
Hence Height = 20 cm.
$2x$ = Base of the triangle = 40 cm