Area Problems The area of an equilateral triangle is ? 243 /4 sq cm. Find the length of its side. 3?3 cm ?3 cm 3 cm 9 cm 3?3 cm ?3 cm 3 cm 9 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP According to the question,area = ?3a2/4 = ?243 /4? a2 = ?81 x 3/?3 ? a = ?9 = 3 cm
Area Problems The perimeter of an equilateral triangle is 90 cm. Find its area. 151?3 sq cm 135?3 sq cm 250?3 sq cm 225?3 sq cm 151?3 sq cm 135?3 sq cm 250?3 sq cm 225?3 sq cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Given that, perimeter = 90 cm? 3a = 90 cm [a = side]? a = 90/3 = 30 cm? Area = ?3a2 / 4 = ?3/4 x (30)2= 900 x ?3/4 = 225?3 sq cm
Area Problems The diameter of a wheel is 63 cms. Distance travelled by the wheel in 100 revolutions is? 198 meters 99 meters 63 meters 136 meters 198 meters 99 meters 63 meters 136 meters ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Distance travelled in 1 revolution = circumference of the wheel = ?d= ( 22/7 ) x 63= 198 cmSo the distance travelled in 100 revolutions = 100 x distance travelled in 1 revolution = 100 x 198 cm= 19800 cm = 198 m
Area Problems The length of a rectangle is twice its breadth. If its length is decreased by 5 cm and the breadth is increased by 5 cm, the area of the rectangle is increased by 75 cm 2 . Therefore , the length of the rectangle is? 50 cm 20 cm 40 cm 30 cm 50 cm 20 cm 40 cm 30 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let breadth = b, length = 2b? Area of rectangle = 2b x b = 2b2As per question. ? (2b - 5 ) (b + 5 ) = 2b2 + 75? 5b = 75 + 25? 5b = 100? b = 100 / 5 = 20Hence, length of the rectangle =2b = 2 x 20 = 40 cm.
Area Problems The sides of a triangular board are 13 meters, 14 meters and 15 meters. The cost of paining it at the rate of Rs. 8.75 per m 2 is? Rs. 735 Rs. 722.50 Rs. 688.80 Rs. 730.80 Rs. 735 Rs. 722.50 Rs. 688.80 Rs. 730.80 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP s = (13 + 14 + 15 ) / 2 = 21, s-a = 8 , s-b = 7, s-c= 6? Area to be painted = ? [s(s-a) (s-b) (s-c)]=? [21 x 8 x 7 x 6] m2= 84 m2? Cost of painting = Rs. (84 x 8.75) = Rs. 735
Area Problems The Number of rounds that a wheel of diameter 7/11 m will make in going 4 km, is? 1000 1700 1500 2000 1000 1700 1500 2000 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Number of round = total distance / circumference of wheel.= (4 x 1000) / ?d= (4 x 1000) / ( 22/7 x 7/11) = 2000
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