Area Problems An error 2% in excess is made while measuring the side of a square. The percentage of error in the calculated area of the square is: 2% 4% 2.02% 4.04% 2% 4% 2.02% 4.04% ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 100 cm is read as 102 cm. ∴ A1 = (100 x 100) cm2 and A2 (102 x 102) cm2. (A2 - A1) = [(102)2 - (100)2] = (102 + 100) x (102 - 100) = 404 cm2. ∴ Percentage error = ❨ 404 x 100 ❩% = 4.04%
Area Problems The ratio of the corresponding sides of two similar triangles is 3 : 4, The ratio of their areas is? ? 3: 2 4 : 3 3 : 4 9 : 16 ? 3: 2 4 : 3 3 : 4 9 : 16 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Ratio of similar triangle = Ratio of the square of corresponding sides = (3x)2 / (4x)2 = 9x2 / 16x2 = 9/16 = 9 : 16
Area Problems One side of a parallelogram is 14 cm. Its distance from the opposite side is 16 cm. The area of the parallelogram is? 56? sq. cm 224 sq. cm 112 sq. cm 210 sq. cm 56? sq. cm 224 sq. cm 112 sq. cm 210 sq. cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Area of parallelogram = Side of parallelogram x distance from the opposite side= 14 x 16 cm2= 224 cm2
Area Problems The area of an equilateral triangle is ? 243 /4 sq cm. Find the length of its side. 3?3 cm 9 cm ?3 cm 3 cm 3?3 cm 9 cm ?3 cm 3 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP According to the question,area = ?3a2/4 = ?243 /4? a2 = ?81 x 3/?3 ? a = ?9 = 3 cm
Area Problems The three sides of a triangle are 15, 25 and x units. Which one of the following is correct? 10? x ? 40 10 ? x 10 10 10? x ? 40 10 ? x 10 10 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP In a triangleSum of two sides is always greater than 3rd side i.e., x < 25 + 15 = 40 .....(i)Difference of two sides is always less than 3rd side i.e., 25 - 15 = 10 < x ...(ii) From Eqs. (i) and (ii) , we get 10 < x < 40
Area Problems The difference between the circumference and the radius of a circle is 37 cm. The area of a circle is? 154 sq. cm 111 sq. cm 148 sq. cm 259 sq. cm 154 sq. cm 111 sq. cm 148 sq. cm 259 sq. cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP ? 2?r - r = 37? [(2 x 22/7) -1]r= 37? 37r / 7= 37? r = 7 So, area of the circle =(22/7) x 7 x 7 cm2= 154 cm2
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