Question

If the perimeter of a semicircular protractor of Nitish is $36$ cm, find its diameter.

• A. $20cm$
• B. $14cm$
• C. $45.87cm$
• D. None of these

Answer 1

The correct option is B $14cm$

Perimeter of a semicircular protractor of nitish is $=2r+\pi r=36cm$

$\Rightarrow r(\pi +2)=36$

$\Rightarrow r(\frac{22}{7}+2)=36$

$\Rightarrow r\left(\frac{22+14}{7}\right)=36$

$\Rightarrow r\left(\frac{36}{7}\right)=36$

$\Rightarrow r=\frac{36\times 7}{36}=7cm$

Diameter$=2r=2\times 7=14cm$