Question

If the perimeter of a semi-circular protractor is 36 cm, find its diameter. ( π = 22/7)

Answer 1

Answer:

Diameter of semi- circular protractor = 14 cm

Step-by-step explanation:

Given: perimeter of sem-icircular protractor= 36 cm

perimeter of semicircle= $\pi r + 2r$

To find: Diameter of semi- circular protractor=2r

36 cm=$\pi r+2r$

36= 22/7 x r + 2r

36 x 7 = 22r+14r

36 x 7 =36r

36 x 7/36=r

r=7 cm

Diameter=2r

                =2 x 7

                 =14 cm

Answer 2

${\huge{\purple{\boxed{\pink{\boxed{\bf{\red{Answer}}}}}}}}$

Let, the diameter of the semi circle be d

the perimeter of semi circular protractor = πr

Therefore, πr + 2r = 36

$\: \: \: \: \: \: \: \: \: \: \ \frac{22}{7} r + 2r = 36$

$\: \: \: \: \: \: \: \: \: \: \frac{22r + 14r}{7} = 36$

$\: \: \: \: \: \: \: \: \: \: \: 36r = 36 \times 7$

$\: \: \: \: \: \: \: \: \: \: \: r = \frac{36 \times 7}{36}$

$\: \: \: \: \: \: \: \: \: \: {\bold{\underline{\underline{\sf{r = 7cm}}}}}$

${\bold{\underline{\underline{\sf{Therefore, d = 2r = 2×7 = 14 cm}}}}}$