Class 10 exercise 12.1 1st question
Answers
Answer:
so the question is this
The radii of the two circles are 19 cm and 9 cm respectively. Find the radius of the circle which has a circumference equal to the sum of the circumferences of the two circles.
Step-by-step explanation:
.Let the radius of required circle =r cm
Radius of 1st circle r 1=9 cm
Radius of 2nd circle r 2 =19 cm
As per the question
Circumference of the required circle = Sum of circumference of two circles
Circumference of small circle =2πr 1
=2π×9
=18π
Circumference of small circle =2πr2
=2π×19
=38π
Now,
Circumference of the required circle = Sum of circumference of two circles
2πr=18π+38π
2πr=58π
r= 2π /56π
r=28 cm
Hence, radius of new circle is 28 cm.