12. Areas Related to Circles Mathematics Exercise - 12.1 class 10 Maths in English - CBSE Study
NCERT Solutions for Class 10 Mathematics are carefully prepared according to the latest CBSE syllabus and NCERT textbooks to help students understand every concept clearly. These solutions cover all important 12. Areas Related to Circles with detailed explanations and step-by-step answers for better exam preparation. Each Exercise 12.1 is explained in simple language so that students can easily grasp the fundamentals and improve their academic performance. The study material is designed to support daily homework, revision practice, and final exam preparation for Class 10 students. With accurate answers, concept clarity, and structured content, these NCERT solutions help learners build confidence and score higher marks in their examinations. Whether you are revising a specific topic or preparing an entire chapter, this resource provides reliable and syllabus-based guidance for complete success in Mathematics.
Class 10 English Medium Mathematics All Chapters:
12. Areas Related to Circles
1. Exercise 12.1
Exercise: 12.1
Q.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 circumferences of the two circles.
Solution:
Let the radius of acquired circle = R
And radius of Large circle r1 = 19 cm
Radius of small circle r2 = 9 cm
Then,
2πR = 2πr1 + 2πr2
2πR = 2π (r1 + r2)
R = (r1 + r2)
= 19 + 9
= 28 cm
Q2. The radii of two circles are 8 cm and 6 cm respectively. Find the radius of the circle having area equal to the sum of the areas of the two circles.
Solution:
Let the radius of acquired circle = R
And radius of Large circle r1 = 8 cm
Radius of small circle r2 = 6 cm
Then,
πR2 = πr12 + πr22
πR2 = π (r12 + r22)
R2 = (r12 + r22)
= 82 + 62
= 64 + 36 cm
= 100 cm
R = √100 = 10 cm
Q3. 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.
Q4. 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?
Solution:
Q5. If the perimeter and the area of a circle are numerically equal, then find the radius of the circle.
Solution:
2πr = πr2
2r = r2
2r = r × r
r = 2 unit
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