Trying to find the right answer to this..

Let the radius of the required circle be R and radii of two given circles be r 1 and r 2 , then according to question. πR 2 = πr 1 2 + πr 2 2 ⇒ πR 2 = (r 1 2 + r 2 2 ) ⇒ R 2 = 64 + 36 ⇒ R 2 = 100 ⇒ R = 10 cm.

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.

Areas Related to Circles

Short Answer Type

1. The radii of two circles are 19 cm and 9 cm respectively. Find the radius of the circle which has circumference equal to the sum of the circumference of two circles.

1620 Views

2. The radii of two circles are 8 cm and 6 cm respectively. Find the radius of the circle having its area equal to the sum of the areas of the two circles.

Let the radius of the required circle be R and radii of two given circles be r₁ and r₂, then according to question.
πR² = πr₁² + πr₂²⇒    πR² = (r₁² + r₂²)
⇒    R² = 64 + 36
⇒    R² = 100
⇒    R = 10 cm.

1153 Views

Long Answer Type

3. Fig. 12.3, depicts an archery target marked with its five scoring areas from the centre outwards as Gold, Red, Blue, Black and White. The diameter of the region representing Gold score is 21 cm and each of the other bands is 10.5 cm wide. Find the area of each of the five scoring regions.

Fig. 12.3

977 Views

Short Answer Type

4. The wheels of a car are of diameter 80 cm each. How many complete revolutions does each wheel make in 10 minutes when the car is travelling at a speed of 66 km per hour?

986 Views

Tick the correct answer in the following: If the perimeter and the area of a circle are numerically equal, then the radius of the circle is
(A) 2 units (D) π units
(C) 4 units (D) 7 units.

707 Views