# Circles - Short Revision || CBSE Class 10 Mathematics || Infinity Learn Class 9&10 | Summary and Q&A

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February 25, 2023
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Infinity Learn NEET
Circles - Short Revision || CBSE Class 10 Mathematics || Infinity Learn Class 9&10

## TL;DR

This content provides a comprehensive analysis of multiple-choice questions (MCQs) related to circles in mathematics.

## Key Insights

• ⭕ The Pythagorean Theorem can be used to find the radius of a circle in certain situations.
• 😥 Tangents to a circle are perpendicular to the radius through the point of contact.
• 🟰 In triangles inscribed in circles, angles opposite to equal sides are equal.
• 🔺 Reflex angles can be calculated by subtracting the given angle from 360 degrees.

## Transcript

hello everybody I am Miss by a math educator and we are over here with some mcqs in the chapter Circle so let's start with it try doing this question guys the length of the tangent to a circle from a point P which is 13 centimeter away from the center is 12 you have to find the radius of the circle so obviously you have to make the figure first the... Read More

### Q: How can the radius of a circle be found using the Pythagorean Theorem?

The radius can be found by using the equation R^2 + 12^2 = 13^2, where R is the radius.

### Q: How can the reflex angle POQ be calculated?

The reflex angle POQ can be calculated by subtracting the given angle POQ (100 degrees) from 360 degrees, resulting in 260 degrees.

### Q: How can the length of tangents to a circle be determined?

The length of tangents drawn from an external point to a circle is equal, and it can be calculated using the Pythagorean Theorem.

### Q: How can the semi-perimeter of a triangle be calculated?

The semi-perimeter of a triangle can be calculated by adding the lengths of its sides (AB, BC, and AC) and dividing the sum by 2.

## Summary & Key Takeaways

• The content includes solving MCQs related to finding the radius of a circle using the Pythagorean Theorem.

• It also covers calculating angles and reflex angles in triangles inscribed in circles.

• The content explains how to find the length of tangents to a circle and the semi-perimeter of a triangle.