Area of a Circle for ninth grade: Calculating parts of the circle

Calculate the area of the section painted red given that the area of the circle is 12.

8

Calculate the length of the arc marked in red given that the area of the circle is 24.

$10$

Calculate the area of the section shaded in red given that the area of the circle is 36.

$2$

Calculate the area of the sector marked in red given that the area of the circle is 12.

$2$

Calculate the area of the sector shaded in red given that the area of the circle is 6.

$\frac{5}{6}$

Calculate the area of the section marked in red given that the area of the circle is 18.

$13$

Given a circle whose center O. From the center of the circle go out 2 radii that cut the circle at the points A and B.

Given AO⊥OB.

The side AB is equal to and+2.

Express band and the area of the circle.

$\frac{\pi}{2}[y^2+4y+4]$