Question

Find the area of a sector with a central angle of 170° and a diameter of 9.1 cm. Round to the nearest tenth.

Answer 1

The area of the circle is calculated through the equation,
           A = πr²
where A is the area and r is the radius. An alternate equation can be used,
          A = πD²/4
where D is the diameter. 

Substituting the known value to the equation,
          A = π(9.1 cm)² / 4 
          A = 65.03 cm²

The area of the sector, As, is calculated by multiplying the area of the circle by the ratio of the angle to the whole revolution.
          As = (65.03 cm²) x (170°/360°)
          As = 30.71 cm²

The answer to this question is therefore letter B.