OBC is a sector of a circle with centre o and radius 9cm work out the area of the shaded region as a percentage of the area of sector obc to 1 decimal place

83.7 %

Step-by-step explanation:

To get the area of the shaded region, we will following these steps.

Step one: Get the area of the sector of the circle.

The area of the sector of the circle can be obtained using the formula:

Theta will be 60 degrees because triangle OAD is an equilateral triangle

Hence,

Step Two: Get the area of the equilateral triangle

The area of the equilateral triangle can be got using the formula

The height of the triangle can be got by drawing an imaginary line bisecting the triangle into two parts and applying the Pythagoras' theorem to any of the resulting right-angled triangles formed.

This will be

Thus

Step Three: Subtract the area of the triangle from the area of the sector

Area of the shaded portion =

Step Four: Divide the area of the shaded portion by the area of the entire shape and multiply the result by 100:

Expressing the ratio of the two areas as a percentage, we have

%

a. the are of the rectangle is 18.25

b. 18.25 times two is 36.50

rae me : d

17 1/3

step-by-step explanation: