Question

the diameter of a water glass is 8.2cm. find the circumference. use 3.14 for pi.

Answer 1

hello

to solve this problem, we simply need to use the formula of circumference of a circle

$C=2\pi r$

now, let's write down our data in the question

$\begin{gathered} c=\text{ ?} \\ d=8.2\operatorname{cm} \\ \pi=3.14 \end{gathered}$

in this question, we are given the value of diameter and not radius, so we have to find the radius from the diameter.

the relationship between diameter and radius is

$r=\frac{d}{2}$

now, let's find the radius of the circle

$\begin{gathered} r=\frac{8.2}{2} \\ r=4.1\operatorname{cm} \end{gathered}$

now, we an proceed to solve for the circumference

$\begin{gathered} c=2\pi r \\ c=2\times3.14\times4.1 \\ c=25.748\approx25.75\operatorname{cm} \end{gathered}$

from the calculations above, the circumference of the circle is 25.75cm