First find the area of the rectangle.
Base multiplied by height
= 9x18
= 162 cm^2
Next, find the area of the triangle:
base multiplied by height divided by 2.
We can easily tell that the height is 9cm. The base of the triangle is also 9cm because one of the sides of the rectangle is the base of the triangle.
Base multiples by height divided by 2
= 9x9/2
= 81/2
= 40.5 cm^2
Now that we have the area of both the rectangle and triangle, we can subtract the unshaded part (the triangle) from the shaded part (rectangle).
= 162-40.5
= 121.5 cm^2
Therefore the area of the shaded part is 121.5cm^2