Question

do this question with full solution​

Answer 1

perimeter of semicircular protactor=(2×22/7×7/2)÷2

perimeter of semicircular protactor=22/2

perimeter of semicircular protactor=11cm

area of semicircular protactor=22/7×(7/2)^2

area of semicircular protactor=22/7×49/4

area of semicircular protactor=77/2cm

Answer 2

$\boxed{ \boxed{ \rm{Perimeter \: of \: semi \: circular \: protractor \: = \pi \: r + 2r}}}$

$\rm\red{Given}$

$\rm{Radius \: (r) \: = \: \dfrac{7}{2} \: cm}$

$\rm{Perimeter \: (S) \: = \: r(\pi + 2)}$

$\rm{S = \dfrac{7}{2} \bigg( \dfrac{22}{7} +2 \bigg)}$

$\rm{S = \dfrac{7}{2} \bigg( \dfrac{36}{7} \bigg)}$

$\rm{S = 18} \: cm$

$\boxed{ \boxed{ \sf{\therefore \: Perimeter = 18}}}$

$\boxed{ \boxed{ \rm{Area \: of \: Semi \: circular \: protractor \: (A) \: = \: \dfrac{\pi r^2}{2}}}}$

$\rm{A = \dfrac{\dfrac{22}{7} \bigg( \dfrac{7}{2} \bigg)^{2}}{2}}$

$\rm{A = \dfrac{22}{7} \times \dfrac{49}{4} \times \dfrac{1}{2} }$

$\rm{A = \dfrac{77}{4} } \: {cm}^{2}$

$\boxed{ \boxed{\rm{Area = \dfrac{77}{4} \: cm^2}}}$