Question

Find the area and circumference of each figure below. Use 31 for TI. If neededround your answers to the nearest hundredths place.CODE: Type the numeral answer. NO LABELS! Part a area, circumference, part barea, circumference: For example: 765, 326, 12004, 3563

Answer 1

a) Given a circle of diameter, d, 10mm.

To find the area, A, of a circle, the formula is

`\begin{gathered} A=\pi r^2 \\ Where\text{ }\pi\text{ is taken as 3.14} \\ r\text{ is the radius of the circle} \\ r=(d)/(2)=(10)/(2)=5\text{ mm} \end{gathered}`

Substitute 5 for r into the formula to find the area, A, of a circle.

`\begin{gathered} A=\pi r^2 \\ A=3.14*5^2=3.14*25=78.5\text{ mm}^2 \\ A=78.5\text{ mm}^2 \end{gathered}`

Hence, the area, A, of the circle is 78.5 mm²

To find the circumference, C, of the circle, the formula is

`\begin{gathered} C=2\pi r \\ C=2*3.14*5=31.4\text{ mm} \\ C=31.4\text{ mm} \end{gathered}`

Hence, the circumference, C, of the circle is 31.4 mm

Thus, the answers are

`78.5,31.4`

b) Given a circle of radius, r, is 6 in

To find the area, A, of a circle, the formula is

`\begin{gathered} A=\pi r^2 \\ A=3.14*6^2=3.14*36=113.04\text{ in}^2 \\ A=113.04\text{ in}^2 \end{gathered}`

Hence, the area, A, of the circle is 113.04 in²

To find the circumference, C, of the circle, the formula is

`\begin{gathered} C=2\pi r \\ C=2*3.14*6=37.68\text{ in} \end{gathered}`

Hence, the circumference, C, of the circle is 37.68 in

Thus, the answers are

`113.04,37.68`