Solution:
Given that,
We have to find the area of a semi circle with a radius of 3 cm
The area of semicircle is given as:
[tex]Area\ of\ semicircle = \frac{ \pi r^2}{2}[/tex]
Where, r is the radius
From given,
r = 3 cm
Substituting the values we get,
[tex]Area\ of\ semicircle = \frac{ \pi \times 3^2}{2}\\\\Area\ of\ semicircle = \frac{ \pi \times 9}{2}\\\\Area\ of\ semicircle = 4.5 \pi[/tex]
Thus the area of semicircle is [tex]4.5 \pi\ cm^2[/tex]