Question

Find the area of a lens face with a radius of 15mm.

Answer 1

Given : A lens face with a radius of 15 mm

We need to find the area

So, the lens has the shape of the semi sphere

Consider it a circle

The radius of the circle = r = 15 mm

The area of the circle =

$\pi\cdot r^2$

So, the area of the lens =

$\begin{gathered} \pi\cdot r^2 \\ \\ =3.14\cdot15^2=706.5\operatorname{mm} \end{gathered}$

So, the area of the lens = 706.5 mm^2