To find the angle of the sector, follow the steps below.
Step 01: Find the total area of the circle.
The area (A) of a circle with radius r is:
[tex]A=\pi r^2[/tex]
Knowing that r = 8 cm, then the area is:
[tex]\begin{gathered} A=8^2\pi \\ A=64\pi\text{ cm}^2 \end{gathered}[/tex]
Step 02: Find the central angle.
To find the angle, use proportions.
Knowing that:
When angle = 2π, A = 64π,
Then when angle is x, A = 56π
[tex]\begin{gathered} \frac{x}{2\pi}=\frac{56\pi}{64\pi} \\ \\ \text{ Multiplying both sides by 2}\pi: \\ \frac{x}{2\pi}*2\pi=\frac{56\pi}{64\pi}*2\pi \\ x=\frac{56*2}{64}\pi \\ x=\frac{112}{64}\pi \\ \\ \text{ Dividing both the numerator and the denominator by 16:} \\ x=\frac{\frac{112}{16}}{\frac{64}{16}}\pi \\ x=\frac{7\pi}{4} \end{gathered}[/tex]
Answer: The central angle measure is:
[tex]\frac{7\pi}{4}[/tex]
