Step-by-step explanation:
[tex]a = \pi(r2 - r1)(r2 + r1)[/tex]
A = \pi( 6.5cm - 2.3cm)(6.5cm + 2.3cm)
\pi ( 4.2cm)( 8.8cm)
= \pi ( 36.96cm^)
= 37pi cm^
