Area Problems The area of the sector of a circle, whose radius is 12 meters and whose angle at the centre is 42, is? 79.2 sq. meters 39.6 sq. meters 52.8 sq. meters 26.4 sq. meters 79.2 sq. meters 39.6 sq. meters 52.8 sq. meters 26.4 sq. meters ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Area of the sector = [(22/7) x 12 x 12] x [42°/360°] m2 = 52.8 m2
Area Problems The area of circle is 38.5 sq. cm. Its circumference is? 121 cm 11 cm 22 cm 6.20 cm 121 cm 11 cm 22 cm 6.20 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 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: 4.04% 2.02% 2% 4% 4.04% 2.02% 2% 4% 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 If the diagonals of a rhombus are 4.8 cm 1.4 cm, then what is the perimeter of the rhombus? 20 cm 12 cm 10 cm 5 cm 20 cm 12 cm 10 cm 5 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Perimeter of rhombus= 2 ? d12 + d22 = 2 ?(4.8)2 + (1.4)2= 2 ?23.04 + 1.96 = 2 ?25 = 2 x 5 = 10 cm
Area Problems If the sides of a rectangle are increased by 10% find the percentage increased in its diagonals. 18% 10% 20% 15% 18% 10% 20% 15% ANSWER EXPLANATION DOWNLOAD EXAMIANS APP According to the formula,? Percentage increase in sides = 10%? Percentage increase diagonals = 10%
Area Problems The ratio of the corresponding sides of two similar triangles is 3 : 4, The ratio of their areas is? 4 : 3 3 : 4 9 : 16 ? 3: 2 4 : 3 3 : 4 9 : 16 ? 3: 2 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
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