A circular road of radius 9m is reduced to 7m in radius. The approximate percentage decrease in area

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08 Dec 2016 Percentage

A circular road of radius 9m is reduced to 7m in radius. The approximate percentage decrease in area is:

OPtion

1) 31.5%
2) 65.5%
3) 32.8%
4) 29.6%
5) 65.8%
6) 39.5%
7) 72.3%
8) 42.8%
9) 25.5%
10)None of these

Solution

Reason-
Original area- pi*(9)^2 = 81pi
New area- pi*(7)^2 = 49pi
Percentage decrease= (32pi/81pi)*100= 39.5%

Option 6)

Correct Option: 6 Best Solution (0)