Answer:
see explanation
Step-by-step explanation:
The length of the arc is calculated as
AB = circumference of circle × fraction of circle
(11)
AB = 2πr × [tex]\frac{90}{360}[/tex]
= 2π × 7 × [tex]\frac{9}{36}[/tex]
= 14π × [tex]\frac{1}{4}[/tex]
= [tex]\frac{7}{2}[/tex] π in
(12)
AB = 2πr × [tex]\frac{135}{360}[/tex] ( r = 20 ÷ 2 = 10 )
= 2π × 10 × [tex]\frac{3}{8}[/tex]
= 20π × [tex]\frac{3}{8}[/tex]
= [tex]\frac{60}{8}[/tex] π
= [tex]\frac{15}{2}[/tex] π cm
