Question

What is the approximate circumference of the circle shown below

Answer 1

The simplest formula for circumference is pi times the diameter. To find the diameter, multiply 20.5 by 2, which is 41. Then, multiply 41 by pi to get the circumference (128.80529...). Round that number and you get the approximate circumference of 129 cm. Hope this helps!

Answer 2

The correct option is $\boxed{\bf option A}$ i.e, $\boxed{\bf 129\text{ cm}}$.

Further explanation:

A circle is the set of all points on a plane whose distance from a fixed point is constant.

There are infinite points on the circle and distance of these points from the center of circle is always constant.

The distance from the center of the circle to any point on the circle is called as radius of the circle.

The circumference is the length of the circle and the formula of the circumference $C$ for the circle is as follows:

$\boxed{C=2\pi r}$  …… (1)

Here, $r$ is the radius of the circle and the value of $\pi$ is approximately equal to $3.14$.

The formula of the circumference for circle is terms of diameter is as follows:

$\boxed{C=d\pi}$

Here, $d$ is the diameter of the circle.

The relationship between diameter and the radius is as follows:

$\boxed{d=2r}$.

From attached Figure 1 it is observed that the radius of the circle is $20.5\text{ cm}$.

 

Substitute $r=20.5$ in the equation (1) to obtain the value of circumference $C$ as follows:

$\begin{aligned}C&=2\pi r\\&=2\cdot 3.14 \cdot 20.5\\&=128.74\\ &\approx129\end{aligned}$

Therefore, the circumference of the circle is $\boxed{\bf 129\text{\bf cm}}$.

Thus, the correct option is $\boxed{\bf option A}$.

Learn more:

1. Learn more about circle brainly.com/question/1952668

2. Learn more about radius of circle brainly.com/question/1506955

Answer details:

Grade: Middle school

Subject: Mathematics

Chapter: Circle

Keywords:  Circle, radius of a circle, point, distance, diameter, circumference, d=2r, C=2pir, 129. centimeter, locus of circle, approximate, value, shown below.