Area Problems If the radius of a circle is decreased by 50% , find the percentage decrease in its area. 65% 75% 25% 35% 65% 75% 25% 35% ANSWER EXPLANATION DOWNLOAD EXAMIANS APP let original radius = r and new radius = (50/100) r = r/2 original area = ?r 2 and new area = ? r / 2 2 decrease in area = 3 ?r 2 / 4 * 1 ?r 2 *100 = 75%
Area Problems In a triangle ABC, BC = 5 cm AC = 12 cm and AB = 13 cm. The length of a altitude drawn from B on AC is? 6 cm 7 cm 4 cm 5 cm 6 cm 7 cm 4 cm 5 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP ? s= (13 + 5 + 12) / 2 cm = 15cms-a = 2 cm, s-b = 10 cm and s-c = 3 cm ? Area = ? (15 x 2 x 10 x 3 ) cm2= 30 cm2? (12 x h) / 2 = 30 ? h = 5 cm
Area Problems If the ratio of the area of two square is 9 : 1 the ratio of their perimeters is? 1:3 9:1 3:1 3:4 1:3 9:1 3:1 3:4 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
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. Neither (A) nor (B) is reuired Only statement A is required Only statement B is required Both A & B are required Neither (A) nor (B) is reuired Only statement A is required Only statement B is required Both A & B are required ANSWER EXPLANATION DOWNLOAD EXAMIANS APP From statement (A), 20b = (1/2) × b × h h = 40 cm.
Area Problems The area of circle is 38.5 sq. cm. Its circumference is? 121 cm 6.20 cm 11 cm 22 cm 121 cm 6.20 cm 11 cm 22 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP ? ( 22 x r2) / 7 = 38.5? r2 =(38.5 x 7) /22? r = 3.5 cm? Circumference = 2 x (22/7) x 3.5 cm= 22 cm
Area Problems One side of a parallelogram is 8.06 cm and its perpendicular distance from opposite side is 2.08 cm. What is the approximate area of the parallelogram? 22.56 cm2 12.56 cm2 16.76 cm2 14.56 cm2 22.56 cm2 12.56 cm2 16.76 cm2 14.56 cm2 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Area of parallelogram = Base x Height = 8.06 x 2.08 = 16.76 cm2
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