Area Problems If the radius of a circle is increased by 6%, find the percentage increase in its area. 8.39% 12.36% 15% 17% 8.39% 12.36% 15% 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 The area of circle inscribed in an equilateral triangle is 462 cm . The perimeter of the triangle is? 168 cms 42 ? 3 cms 72.6 cms 126 cms 168 cms 42 ? 3 cms 72.6 cms 126 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 A rectangle has 15 cm as its length and 150 cm 2 as its area .Its area is increased to 1 1 / 3 times the original area by increasing only its length . Its new perimeter is? 80 cm 50 cm 60 cm 70 cm 80 cm 50 cm 60 cm 70 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Breadth of the rectangle = (150/15) cm= 10 cmNew area = (4/3 x 150) cm2= 200 cm2New length = 200/10 cm=20 cmNew perimeters = 2(20 + 10) cm= 60 cm
Area Problems If a regular hexagon is inscribed in a circle of radius, r then its perimeter? 12r 9r 3r 6r 12r 9r 3r 6r ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Length of each side of hexagoan = radius of circle ? its perimeter = 6r
Area Problems Four horses are be tethered at four concern of a square plot of side 63 meters, so that they just cannot reach one another. The area left ungrazed is? 675.5 m2 850.5 m2 785.8 m2 780.6 m2 675.5 m2 850.5 m2 785.8 m2 780.6 m2 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Area left ungrazed = [(63 x 63) - (4 x 1/4 x 22/7 x (63/2)2] m2= (63 x 63 - (99 x 63)/2 ) m2= 63 x (63 - 99/2) m2= 850.5 m2
Area Problems The diagonals of a squares is 4?2 cm. The diagonal of another square whose area is double that of the first square is 8 cm 8?2 cm 6 cm 4?2 cm 8 cm 8?2 cm 6 cm 4?2 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Diagonal of square = ?2a [a = side]4?2 = ?2 a a = 4 cmNow, area of square = a2 = (42) = 16Side of a square whose area is 2 x 16.a12 = 32 ? a1 = ?32 ?a14?2Now, diagonal of new square = ?2a = ?2x 4 ?2 = 8 cm
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