Area Problems The ratio of the radii of two circle is 1:3 the radio of their areas is? 1:6 None of these 1:9 1:3 1:6 None of these 1:9 1:3 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP The Radio of areas = area of first circle : area of 2nd circle= ?r2 / ?(3r)2= ?r2/ 9 ?r2= 1/9 = 1: 9
Area Problems The area of an equilateral triangle whose side is 8 cms is? 16?3 cm2 21.3 cm2 64 cm2 4?3 cm2 16?3 cm2 21.3 cm2 64 cm2 4?3 cm2 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Req. Area = ?3/4 x a2 = ?3/4 x 82 cm2= 16?3 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. Only statement A is required Neither (A) nor (B) is reuired Both A & B are required Only statement B is required Only statement A is required Neither (A) nor (B) is reuired Both A & B are required Only statement B is required ANSWER EXPLANATION DOWNLOAD EXAMIANS APP From statement (A), 20b = (1/2) × b × h h = 40 cm.
Area Problems One side of a rectangular field is 4 meter and its diagonal is 5 meter. The area of the field is? 20 m 2 12 m2 4?5 m2 15 m2 20 m 2 12 m2 4?5 m2 15 m2 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Other side = ?5 2 - 42 = ? 9=3 mSo The area of the rectangular field = 4 x 3 = 12 m2
Area Problems The perimeter of an isosceles triangle is equal to 14 cm . The lateral side is to the base in the ratio 5 : 4 the area of the triangle is? 3/2?21 cm2 2?21 cm2 ?212 1/2?21 cm2 3/2?21 cm2 2?21 cm2 ?212 1/2?21 cm2 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let lateral side = (5y) cm and base = (4y) cm ? perimeter = 5y + 5y + 4y = 14 ?y = 1So, the sides are 5 cm , 5 cm and 4 cm Now s= 1/2 (5 + 5 + 4) cm = 7 cm (s-a) = 2 cm (s-b) = 2 cm and (s-c) = 3 cm? Required Area = ? (7 x 2 x 2 x 3) cm2=2?21 cm2
Area Problems If the radius of a circle is increased by 6%, find the percentage increase in its area. 15% 8.39% 17% 12.36% 15% 8.39% 17% 12.36% 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%
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