Q1. In a rectangle the ratio of the length and breadth is 3:2. If each of the length and breadth is increased by 4m their ratio becomes 10:7. The area of the original rectangle in m² is?
A. 846
B. 864
C. 840
D. 876
Answer: B
Explanation:
[latex] [3x + \frac {4}{2x + 4}] = \frac {10}{7} [/latex]
[latex]x = 12 [/latex]
Area of the original rectangle = [latex] 3x \times 2x = 6x² [/latex]
Area of the original rectangle = [latex] 6 \times 144 = 864 m² [/latex]
Q2. The perimeter of a rectangle and a square is 160 cm each. If the difference between their areas is 500 cm. If the area of the rectangle is less than that of a Square then find the area of the rectangle?
A. 1800 cm²
B. 1500 cm²
C. 1100 cm²
D. 1600 cm²
Answer: C
Explanation:
Perimeter of rectangle = Perimeter of Square = 160
4a = [latex] 160 \Rightarrow a [/latex] = 40
Area of square = 1600
1600 – lb = 500
lb = 1100 cm²
Q3. Circumference of a circle A is [latex] \frac {22}{7} [/latex] times perimeter of a square. Area of the square is 441 cm². What is the area of another circle B whose diameter is half the radius of the circle A(in cm²)?
A. 354.5
B. 346.5
C. 316.5
D. 312.5
Answer: B
Explanation:
Area = 441 cm²
a = 21 cm
Perimeter of Square = [latex] 4 \times 21 [/latex]
Circumference of a Circle = [latex] 4 \times 21 \times \frac {22}{7} [/latex]
2 [latex] \pi r = 4 \times 3 \times 22 [/latex]
r = [latex] \frac {12 \times 22 \times 7}{2} \times 22 [/latex] = 42 cm
Radius of Circle B = [latex] \frac {42}{4} [/latex] = 10.5 cm
Area of Circle = [latex] \pi r² = \frac {22}{7} \times 10.5 \times 10.5 [/latex] = 346.5 cm²
Q4. The area of a rectangle is equal to the area of a square whose diagonal is [latex] 12 \sqrt {2} [/latex] meter. The difference between the length and the breadth of the rectangle is 7 meter. What is the perimeter of a rectangle ? (in meter).
A. 68 meter
B. 50 meter
C. 62 metre
D. 64 metre
Answer: B
Explanation:
d = [latex] a \sqrt {2} [/latex]
[latex] 12 \sqrt {2} = a \sqrt {2} [/latex]
a = 12
[latex] l \times b [/latex] = a² = (12²) = 144
l – b = 7
l = b + 7
[latex] (b + 7) \times (b) [/latex]= 144
b² + 7b – 144 = 0
b = 9
l = 16
2(l + b) = 2(16 + 9) = 50 m
Q5. The area of a rectangle gets reduced by 9 square units, if its length is reduced by 5 units and breadth is increased by 3 units. If we increase the length by 3 units and breadth by 2 units, then the area is increased by 67 square units. Find the area of the rectangle?
A. 159 m
B. 179 m
C. 147 m
D. 153 m
Answer: D
Explanation:
Length = [latex] x [/latex]
Breadth = [latex] y [/latex]
[latex] xy – (x-5)(y+3) [/latex] = 9
[latex] 3x – 5y – 6 [/latex]= 0 ................(i)
[latex] (x+3)(y+2) – xy [/latex] = 67
[latex] 2x + 3y -61 [/latex] = 0 ................(ii)
solving (i) and (ii)
[latex] x = 17 m [/latex]
[latex] y = 9 m [/latex]
Area of the Rectangle = 153 m