Mathematics

In the diagram above, QR is in the diameter of the semicircle QR. Find the…

In the diagram above, QR is in the diameter of the semicircle QR. Find the area of the figure to the nearest whole number. [(pi = frac{22}{7})]

  • A.
    89 cm2
  • B.
    70 cm2
  • C.
    90 cm2
  • D.
    80 cm2
Correct Answer: Option A
Explanation

Area of rectangle PQRS = (10 times 7 = 70cm^2)

Area of semi-circle: (frac{pi r^{2}}{2})

r = (frac{7}{2} cm)

Area of semi-circle = (frac{1}{2} times frac{22}{7} times frac{7}{2} times frac{7}{2})

= (frac{77}{4} = 18.75 cm^{2})

Area of figure = ((70 + 18.75) cm^{2})

= 88.75 cm(^{2} approxeq) 89 cm(^{2})