Question

A triangle is equal in area to a rectangle which measures 10cm by 9cm. If the base of the triangle is 12cm long, find its altitude

Answer 1

h = 15 cm

Explanation:

Area of triangle equals the area of rectangle. As the dimensions of the rectangle is given, we can first find the area of the rectangle.

`\boxed{\bf Area \ of \ the \ rectangle = length * width}`

= 10 * 9

= 90 cm²

Area of triangle = area of rectangle

= 90 cm²

base of the triangle = b = 12 cm

`\boxed{\bf Area \ of \ triangle = (1)/(2)bh}` where h is the altitude and b is the base.

`\bf (1)/(2) b* h = 90 \\\\(1)/(2)*12* h = 90`

`\bf h = (90*2)/(12)\\\\\boxed{\bf h = 15 \ cm}`