Question

Text: these two triangles are similar

Values from left to right: 10, 12, 9

What is the area of the shaded area

Answer 1

26.25 cm²

Explanation:

The area of the shaded part is the area of the shaded triangle subtract the area of the white triangle.

Since the triangles are similar then the ratios of corresponding sides are equal.

let the height of the white triangle be h, then

`(12)/(9)` =
`(10)/(h)` ( cross- multiply )

12h = 90 ( divide both sides by 12 )

h = 7.5

shaded area =
`(1)/(2)` × 12 × 10 -
`(1)/(2)` × 9 × 7.5 = 60 - 33.75 = 26.25 cm²