Q:

If each side of a square is increased by 25%, find the percentage change in its area?

A) 65.25 B) 56.25
C) 65 D) 56
 
Answer & Explanation Answer: B) 56.25

Explanation:

let each side of the square be a , then area = a x a

As given that The side is increased by 25%, then

New side =  = 

New area = 

increased area= 

Increase %=  % = 56.25%

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129 28632
Q:

If the radius of a circle is decreased by 50%, find the percentage decrease in its area.

A) 55% B) 65%
C) 75% D) 85%
 
Answer & Explanation Answer: C) 75%

Explanation:

Let original radius = R.

New radius = 

Original area =  and new area = 

Decrease in area =  = 75%

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36 13605
Q:

A man walked diagonally across a square lot. Approximately, what was the percent saved by not walking along the edges?

A) 30 B) 40
C) 50 D) 60
 
Answer & Explanation Answer: A) 30

Explanation:

Let the side of the square(ABCD) be x meters.

Then, AB + BC = 2x metres.

AC =  = (1.41x) m.

Saving on 2x metres = (0.59x) m.

Saving % = = 30% (approx)

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22 11723
Q:

If the diagonal of a rectangle is 17cm long and its perimeter is 46 cm. Find the area of the rectangle.

A) 110 B) 120
C) 130 D) 140
 
Answer & Explanation Answer: B) 120

Explanation:

let length = x and breadth = y then

2(x+y) = 46    x+y = 23

x²+y² = 17² = 289

now (x+y)² = 23²

x²+y²+2xy= 529

289+ 2xy = 529

 xy = 120

area = xy = 120 sq.cm

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28 8360
Q:

The length of a rectangular hall is 5m more than its breadth. The area of the hall is 750 m. The length of the hall is

A) 20 B) 25
C) 30 D) 35
 
Answer & Explanation Answer: B) 25

Explanation:

Let breadth = x m

Then, length = (x+5)m

x(x+5) = 750 

x² + 5x - 750= 0

(x+30)(x-25)= 0

x = 25

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22 8244