Question

An umbrella has 8 ribs which are equally spaced. Assuming the umbrella to be a flat circle of radius 45 cm, find the area between two consecutive ribs of the umbrella.

• A. $769c{m}^2$
• B. $794.8c{m}^2$
• C. $798.6c{m}^2$
• D. $700c{m}^2$

Answer 1

The correct option is B

$794.8c{m}^2$

Number of ribs in umbrella = 8
Radius of umbrella = 45 cm
Area between the two consecutive ribs of the umbrella
= $\frac{Totalarea}{Numberofribs}$
$Totalarea=\pi r^2=3.14\times (45{)}^2=6358.5c{m}^2$
$\therefore$ Area between the two consecutive ribs
$=\frac{6358.5}{8}$ $=794.8c{m}^2$