Area Problems The length of minute hand of a wall clock is 7 cms. The area swept by minute hand in 30 minutes is? 77 sq. cm 154 sq. cm 210 sq. cm 147 sq. cm 77 sq. cm 154 sq. cm 210 sq. cm 147 sq. cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Angle swept in 30 min= 180° Area swept = [(22/7) x 7 x 7] x [180°/360°] cm2 = 77 cm2
Area Problems The question given below contain two statements giving certain data. You have to decide whether the data given in the statements are sufficient for answering the question ? Question : What is the height of a right-angled triangle ? Statements : A. The area of the triangle is 20 times its base. B. The perimeter of the triangle is equal to that of a square of the side 10 cm. Both A & B are required Neither (A) nor (B) is reuired Only statement B is required Only statement A is required Both A & B are required Neither (A) nor (B) is reuired Only statement B is required Only statement A is required ANSWER EXPLANATION DOWNLOAD EXAMIANS APP From statement (A), 20b = (1/2) × b × h h = 40 cm.
Area Problems The ratio of the area of two square, one having and double its diagonal than the other is? 4:1 3:2 3:1 2:1 4:1 3:2 3:1 2:1 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the diagonal of one square be (2d) cmThen, diagonal of another square = d cm? Area of first square = [ 1/2 x (2d)2] cm2Area of second square = (1/2 x d2) cm2? Ratio of area = (2d)2/ d2= 4/1 = 4: 1
Area Problems if the side of a square be increased by 4 cms. The area increased by 60 sq. cms . The side of the square is? 12 cm None of these 14cm 13 cm 12 cm None of these 14cm 13 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let each side = x cmThen, (x + 4 )2 - x2 = 60? x 2 + 8x + 16 - x2 = 60? x = 5.5 cm
Area Problems If the sides of a squares is increased by 25%, then the area of the squares will be increased by 125% 50% 53.75% 56.25% 125% 50% 53.75% 56.25% ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Required increment = 2a + [a2 / 100] %= 2 x 25 + [(252)/100)] %= 50 + (625/100)% = 56.25%
Area Problems If the radius of a circle be reduced by 50%. Its area is reduced by? 31.5% 65.5% 39.5% 34.5% 31.5% 65.5% 39.5% 34.5% ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Original area = ? x (r/2)2 = ?r2/4Reduction in area = ? r2 - 3? r2/4? Reduction per cent = [ 3?r2/4 x 4/(?r2) x 100 ] %= 75%
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