Area Problems In a circle of radius 21 cm an arc subtends an angle of 72° at the centre. The length of the arc is? 21.6 cm 13.2 cm 26.4 cm 19.8 cm 21.6 cm 13.2 cm 26.4 cm 19.8 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Arc length = 2?r (?° / 360°) = 2 x (22/7) x 21 x (72° / 360°) cm= 26.4 cm
Area Problems The diagonals of two squares are in the ratio of 3 : 2. Find the ratio of their areas. 9 : 4 9 : 7 9 : 2 9 : 5 9 : 4 9 : 7 9 : 2 9 : 5 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the diagonals of the squares be 3x and 2x.? Ratio of their areas = [(1/2) (3x2)] / [(1/2) (2x2)] = 9/4
Area Problems The area of circle inscribed in an equilateral triangle is 462 cm . The perimeter of the triangle is? 72.6 cms 126 cms 168 cms 42 ? 3 cms 72.6 cms 126 cms 168 cms 42 ? 3 cms ANSWER EXPLANATION DOWNLOAD EXAMIANS APP ? 22/7 x r2 = 462? r2 = (462 x 7) /22 = 147? r = 7?3 cm ? Height of the triangle = 3r = 21?3 cmNow, ? a2 = a2/4 + (3r)2? 3a2/4 = (21?3)2? a2 = (1323 x 4)/3? a = 21x 2 = 42 cm? Perimeter = 3a = 3 x 42=126 cm
Area Problems If the radius of a circle is increased by 6%, find the percentage increase in its area. 8.39% 15% 12.36% 17% 8.39% 15% 12.36% 17% ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Given that, a = 6 According to the formula,Percentage increase in area= 2a + [a2/100]%= 2 x 6 + [36/100]%= (12 + 0.36)%= 12.36%
Area Problems A room 5m 55cm long and 3m 74cm broad is to be paved with square tiles.Find the least number of square tiles required to cover the floor? 166 186 156 176 166 186 156 176 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Area of the room=(544 * 374) size of largest square tile= H.C.F of 544 & 374 = 34 cm Area of 1 tile = (34 x 34) c m 2 Number of tiles required== [(544 x 374) / (34 x 34)] = 176
Area Problems The area of an equilateral triangle whose side is 8 cms is? 16?3 cm2 4?3 cm2 21.3 cm2 64 cm2 16?3 cm2 4?3 cm2 21.3 cm2 64 cm2 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Req. Area = ?3/4 x a2 = ?3/4 x 82 cm2= 16?3 cm2
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