CBSE Class 10 Mathematics Standard 2025: question 25
Set in the CBSE Class 10 board exam of 2025, paper 30/1/1, section B, question 25, for 2 marks. Try it first; the hints and our step-by-step solution are below.
Q25 · 2 marks · Very short answerCircles
A person is standing at P outside a circular ground at a distance of 26 m from the centre of the ground. He found that his distances from the points A and B on the ground are 10 m (PA and PB are tangents to the circle). Find the radius of the circular ground.
Figure in the paper: Circle with centre O. External point P on the left, PO = 26 m drawn. Tangents PA and PB (each 10 m) touch the circle at A (top) and B (bottom). OA and OB are joined. See it in the official paper.
Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 30/1/1.
Hints
Open one hint at a time and try again before the next.
Hint 1
What angle does a radius make with the tangent at the point of contact?
Hint 2
Use Pythagoras theorem in with OP as the hypotenuse.
Step-by-step solution
Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.
- ½ mark
[tangent ⟂ radius at the point of contact].
- 1 mark
In right , by Pythagoras theorem:
- ½ mark
. Radius of the ground m.
Answer: Radius = 24 m
Where the marks are
- States (½ mark)
- Applies Pythagoras: (1 mark)
- Radius = 24 m (½ mark)
Revise the chapter
- Chapter: Circles (notes, formulas, where marks are lost and every past question)
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The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.