Question 14 - Area of combination of figures : sector based - Chapter 11 Class 10 Areas related to Circles

Last updated at July 30, 2026 by

Ex 12.3, 14 - AB and CD are arcs of two concentric circles - Ex 12.3

Ex 12.3, 14 - Chapter 12 Class 10 Areas related to Circles - Part 2
Ex 12.3, 14 - Chapter 12 Class 10 Areas related to Circles - Part 3

Take a fresh quiz. Then take another.
Every attempt is a new AI-adaptive Teachoo quiz with 5 questions, selected from your answers, mistakes, and progress.
Remove Ads

Transcript

Question 14 AB and CD are respectively arcs of two concentric circles of radii 21 cm and 7 cm and centre O (see figure). If AOB = 30 , find the area of the shaded region. Area of shaded region = Area of sector AOB Area of sector COD Area of sector AOB radius = r = 21 cm & = 30 Area of sector AOB = /360 r2 = 30/360 22/7 21 21 = 1/12 22 3 21 = 231/2 cm2 Area of sector COD radius = r = 7 cm & = 30 Area of sector COD = /360 r2 = (30 )/360 22/7 (7)2 = 1/12 22/7 7 7 = 77/6 cm2 Now , Area of shaded region = Area of Sector OAB Area of sector OCD = 231/2 77/6 = (3 231 77)/6 = (693 77)/6 = 616/6 = 308/3 cm2 Hence, area of shaded region = 308/3 cm2

Davneet Singh's photo - Co-founder, Teachoo

Made by

Davneet Singh

Davneet Singh is an IIT Kanpur graduate and has been teaching for 16+ years. At Teachoo, he breaks down Maths, Science and Computer Science into simple steps so students understand concepts deeply and score with confidence.

Many students prefer Teachoo Black for a smooth, ad-free learning experience.