Question

how can solve that plz explaine to use formulaes​

Answer 1

Answer:

9π or 36π

Step-by-step explanation:

I am not doing the calculation but I can tell you how to do the question!

First of all take out the area of the full circle by π$r^{2}$ and divide the area by '2'

Then using BC as radius of semi circle take its area out by formula π$r{2}$/2

Then subtract the smaller area from the larger area then you have the area of the shaded region of the upper part but, to calculate the full region add the smaller area to complete the question.

Basic Keywords:-

Diameter = 2 X Radius and Radius = 1/2 Diameter

Area of circle = π$r^{2}$

Area of semi-circle = Area of circle / 2

AB = Radius of the full circle

AD is the diameter of greater circle

BC = CD

Answer 2

Answer:

Option B 27π

Step-by-step explanation:

Use of formula A=πr² for circles

• Area of circle with diameter AD is 81 π as AD=9
• Area of circle with diameter AB is 9π as AB=AD/3=9/3=3
• Area of circle with diameter BD is 36 π as BD=BC+CD=AB*2=3*2=6

Shaded area equals to:

• 81π /2+9π /2-36π /2=27π

Option B 27π  is correct