Q. Circumference of a circle is 44 cm.Find it's area.
Ans. The formula for finding the area of the circle when the circumference is given is as below.
A =
A =
A =
If you find the radius from the circumference and then calculate area from radius you have to do 6 steps,3 steps for calculating the radius and 3 steps for calculating the area.
With the above formula, you avoid 4 steps and get the answer in just 2 steps.
Q. Perimeter of a semicircle is 72 cm.Find it's radius.
Ans. The formula for finding the radius of the semicircle when the perimeter is given is as below.
'P' is the perimeter of the semicircle and 'r ' is the radius.
r = 14 cm
If you find the radius from the perimeter of the semicircle you have to do it in 4 steps.
But with the above formula, you get the answer in just one step.
Q. The breadth of a rectangle is increased by 20%. At what percent the length be decreased to maintain the same area.
Ans. The formula for finding the percentage decrease in length is as below.
The percentage decrease in length =
Where 'X' is the percentage increase in breadth.
The percentage decrease in length =
The percentage decrease in length = 50/3 %
If you find the percentage decrease in length by doing the calculation you have to do it in 6steps. But with the above formula, you get the answer in just two steps.
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