Answer :
Given:
The diameter of the circle is, D = 10.
The objective is to find the area of the circle.
The radius of a circlie is half of the diamteter of the cilrcle.
[tex]\begin{gathered} r=\frac{D}{2} \\ =\frac{10}{2} \\ r=5\text{ } \end{gathered}[/tex]The area of a circle can be calculated as,
[tex]\begin{gathered} A=\pi r^2 \\ =\pi\cdot5^2 \\ =25\pi \\ =78.5\text{ } \end{gathered}[/tex]Hence, the area of the circle is 78.5 sq. units.