The radius of the circle is increased by 5 cm. How much will the circumference of this circle increase?

The circumference is calculated using the formula:

l = 2пr;

Let’s say the initial radius of the circle was r1 cm, then the radius after the increase will be (r1 + 5) cm. Find the lengths of the circles:

l1 = 2пr1;

l2 = 2п (r1 + 5) = 2пr1 + 10п;

l2 – l1 = (2пr1 + 10п) – 2пr1 = 10п cm.

Answer: d) 10п see.



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