1. The diameter of a circle is 90 cm less than the circumference. What is the diameter of the circle?
a) 42 cm
b) 44 cm
c) 43 cm
d) 45 cm
Answers
Answered by
2
Answer:
option d is correct (45)centimetres
Answered by
1
The diameter of the circle
a) 42 cm
It is given in the question that the diameter of a circle is 90cm less than that of the circumference.
We know that for a circle of radius r, its diamter is 2r and its circumference is equal to 2Пr.
Therefore,
2Пr - 2r = 90
⇒ 2r (П-1) = 90
Taking П as 22/7, П-1 becomes 22/7 - 1 = 15/7
⇒ 2r(15/7) = 90
⇒ 2r = 90*7/15
⇒ 2r = 42
Thus, diameter, 2r = 42cm
Option (a) is correct.
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