Areas
Practice Questions - Areas
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Q13) The length of the wire which is tied as a boundary of a semicircular park is 72 m. Find the area of the park. 1) 154 m2 2) 308 m2 3) 77 m2 4) 616 m2
Boundary of a semicircular park = 72 m  Therefore, radius of semicircular park = 14 m Area of semicircular park = (1/2)πr2 = (1/2)×(22/7)×14×14 = 308 m2 Hence, option 2. Q14) A piece of land is circular in shape with a radius of 70 m. Find the cost of fencing this piece of land at the rate of Rs 3 per m ? 1) Rs 660 2) Rs 1320 3) Rs 1980 4) Rs 440
Total Cost of fencing the circular piece of land = Circumference of the circle × Cost of fencing per m Radius of the circle, r =70 m Circumference of the circle = 2πr = 2×(22/7)×70 = 440 m Cost of fencing per m = Rs 3 Total Cost of fencing the circular piece of land = 440 × 3 = Rs 1320 Hence, option 2. Q15) Which of the following can be the area of a triangle whose two sides are 7 cm and 9 cm. 1) 30.83 cm2 2) 31.61 cm2 3) 33.42 cm2 4) All of the above
Maximum area of a triangle with sides 7 cm and 9 cm is (1/2) × 7 × 9 = 31.5 cm2 Hence, option 1. Q16) Cost of turfing a rectangular garden is Rs 1.5 per cm2. If the length of the garden is 100 cm whereas, its breadth is 50 cm. Find the cost of turfing the entire garden? 1) Rs 750 2) Rs 7500 3) Rs 1500 4) Rs 5000
Total Cost of turfing the garden = Area of the garden × Cost of turfing per cm2 Area of the garden = L × B = 100 × 50 = 5000 cm2 Cost of turfing a rectangular garden = Rs 1.5 per cm2 Total Cost of turfing the garden = 5000 × 1.5 = Rs 7500 Hence, option 2. |