Answer:
Explanation:
10a)
The formula for determining the area of a sector is expressed as
Area = #/360 × πr^2
From the diagram given,
# = π/3. We would convert π to degrees. 2π = 360 degrees. It means that π = 360/2 = 180 degrees. Therefore
π/3 = 180/3 = 60 degrees.
r = 10
Area of sector = 60/360 × 3.14 × 10^2 = 52.33 cm^2
Area of the triangle formed can be determined by the formula,
Area = 1/2abSinC
From the triangle,
a = 10,
b = 10
C = π/3 = 60 degrees. Therefore,
Area = 1/2 × 10 × 10 × Sin60 = 50 × 0.8660
Area of triangle = 43.3 cm^2
Therefore, area of the shaded region would be
53.3 - 43.3 = 10 cm^2
10b) looking at the diagram,
# = 135 degrees
r = 12
Area of sector = 135/360 × 3.14 × 12^2 = 169.56 cm^2
Area of the triangle = 1/2 × 12 × 12 × Sin 135 = 1/2 × 144 × 0.7071 = 50.9 cm^2. Therefore, the area of the shaded region would be
169.56 - 50.9 = 114.66 cm^2