**Formula** for Area of circle

The formula to find a circle's area $$ \pi $$ (radius)^{2} usually expressed as $$ \pi \cdot r^2 $$ where r is the radius of a circle.

The area of a circle is all the space inside a circle's circumference.

In the picture, the area of the circle is the part of the circle that is changing color.

**Practice** Problems

Remember the Formula:

$$ Area = \pi \cdot r^2 \\ A = \pi \cdot ( 22')^2 \\ A = \pi \cdot 484 \\ A = \pi \cdot 1520.53084433746 \text{ square feet} \\ \\ Area = \boxed{ 1520.5 } \\ \text {Rounded to nearest tenth} $$

Remember the Formula:

$$ Area = \pi \cdot r^2 \\ A = \pi \cdot ( 5")^2 \\ A = \pi \cdot 25 \text{ square inches} \\ A = 78.53981633974483 \text{square inches} \\ A = 78.5 \\ \text{ square inches, rounded to nearest tenth} $$

Remember the Formula:

$$ Area = \pi \cdot r^2 \\ A = \pi \cdot (7 \text{ centimeters} )^2 \\ A = 153.93804002589985 \text{ square centimeters} \\ \boxed { A = 153.94 } \\ \text{ square centimeters, rounded to nearest hundredth} $$