we know that
The area of a circle is
[tex]A=\pi\cdot r^2[/tex]
we have
r=30 yd
substitute
[tex]\begin{gathered} A=\pi\cdot(30)^2 \\ A=900\pi\text{ yd\textasciicircum{}2} \end{gathered}[/tex]
The area of full circle is 900pi square yards
Find out the area of 90 degrees sector
Remember that
The area of a 90 degrees sector is one fourth of the area of the full circle
so
[tex]\begin{gathered} A=(\frac{1}{4})\cdot900\pi \\ A=225\pi\text{ yd\textasciicircum{}2} \\ \end{gathered}[/tex]
therefore
the area of a 90 degrees sector is 225pi square yards
