Area Problems A rectangle has 20 cm as its length and 200 sq cm as its area. If the area is increased by 1 1/ 5 time the original area by increase its length only then the perimeter of the rectangle so formed (in cm) is 60 72 64 68 60 72 64 68 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP l1 = 20 cm, A1 = 200 sq cm? b1 = 200/20 = 10 cmNow, A2 = 200 x 6/5 = 240 sq cm b2 = 10 cm? l2 = 240/10 = 24 cm? Perimeter of new rectangle = 2(l2 + b2)= 2(24 + 10) = 2 x 34 = 68 cm
Area Problems The area of circle inscribed in an equilateral triangle is 462 cm . The perimeter of the triangle is? 42 ? 3 cms 168 cms 126 cms 72.6 cms 42 ? 3 cms 168 cms 126 cms 72.6 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 Square units 13 by 9 of an office area is 107 97 127 117 107 97 127 117 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Square units 13 by 9 of an office means office of length 13 units and breadth 9 units. Now its area is 13x 9 = 117 square units or units square.
Area Problems A rectangular field is to be fenced on three sides leaving a side of 20 feet uncovered. If the area of the field is 680 sq. feet, how many feet of fencing will be required? 40 34 88 68 40 34 88 68 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP We have: l = 20 ft and lb = 680 sq. ft. So, b = 34 ft. ∴ Length of fencing = (l + 2b) = (20 + 68) ft = 88 ft
Area Problems The length of each side of an equilateral triangle having an area of 4?3 cm 2 is? 3 cm ?3/4 cm 4/?3 cm 4 cm 3 cm ?3/4 cm 4/?3 cm 4 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Area of equilateral triangle = ?3/4 a2 = 4?3.? a2 = 16? a = 4 cm
Area Problems If the ratio of the area of two square is 9 : 1 the ratio of their perimeters is? 3:4 3:1 9:1 1:3 3:4 3:1 9:1 1:3 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the area of square be (9x)2 m2 and (x2) m2Then, their sides are (3x) m and x metres respectively? Ratio of their perimeters = 12x / 4x=3:1
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