If the radius of a sector is 7cm and \$\theta = 90^0\$. Find the area?

Area of a sector.

A = \$\frac{\theta}{360^\circ} \times \pi r^2\$

Substitute \$22/7\$ for \$pi\$, \$90^\circ\$ for \$\theta\$ and 7 for r.

\$A = \frac{90°}{360°} \times \frac{22}{7} \times 7 \times 7 \$

Cancel out common factor.

\$A = \frac{\cancel{90°} ^{1}}{\cancel{360°} ^{4}} \times \frac{22}{\cancel{7}^{1}} \times \cancel{7}^{1} \times 7 \$

Cancel out common factor.

\$ A = \frac{1}{2} \times \frac{11}{1} \times 1 \times 7 \$

Multiply.

A = \$\frac{1}{2} \times \frac{11}{1} \times 1 \times 7\$

Divide.

\$A= 38.5\$

Answer

The area is \$38.5 cm^2\$.