Question

Taking ∏=3.14 .Find perimeter and area of circle whose radius is
1.8cm
2.15cm
3.20cm

Answer 1

Hint: Here we are given a value of radius of three different circles. We have to find the value of the perimeter and area of all these circles. So let’s use the formula to find them.
Formula used:
Perimeter of circle \[ = 2\pi r\]
Area of circle \[ = \pi {r^2}\]

Complete step-by-step answer:

We will find the perimeter and area of all circles separately.
r=8cm
Perimeter of circle \[ = 2\pi r\]
 \[
   \Rightarrow 2 \times 3.14 \times 8 \\
   \Rightarrow 50.24cm \\
\]
 area of circle \[ = \pi {r^2}\]
 \[
   \Rightarrow 3.14 \times {8^2} \\
   \Rightarrow 3.14 \times 64 \\
   \Rightarrow 200.96c{m^2} \\
\]
r=15cm
Perimeter of circle \[ = 2\pi r\]
  \[
   \Rightarrow 2 \times 3.14 \times 15 \\
   \Rightarrow 94.2cm \\
\]
 Area of circle \[ = \pi {r^2}\]
\[
   \Rightarrow 3.14 \times {15^2} \\
   \Rightarrow 3.14 \times 225 \\
   \Rightarrow 706.5c{m^2} \\
\]
 r=20cm
 Perimeter of circle \[ = 2\pi r\]
\[
   \Rightarrow 2 \times 3.14 \times 20 \\
   \Rightarrow 125.6cm \\
\]
Area of circle \[ = \pi {r^2}\]
 \[
   \Rightarrow 3.14 \times {20^2} \\
   \Rightarrow 3.14 \times 400 \\
   \Rightarrow 1256c{m^2} \\
\]
Now we have found the perimeters and areas for all three circles.

Note:Here we have to find the perimeters and areas of the circles with the given radius. So just use the formulas provided. Also don’t forget to write the units of perimeter and area.