English

In the following figure, write BC, AC, and CD in ascending order of their lengths.

Advertisements
Advertisements

Question

In the following figure, write BC, AC, and CD in ascending order of their lengths.

Sum
Advertisements

Solution

In ΔABC,

AB = AC

⇒ ∠ABC = ∠ACB  ..(angles opposite to equal sides are equal)

⇒ ∠ABC = ∠ACB = 67°

⇒ ∠BAC = 180° - ∠ABC - ∠ACB   ...(Angle sum property)

⇒ ∠BAC = 180° - 67° - 67°

⇒ ∠BAC = 46°

Since ∠BAC < ∠ABC, we have

BC < AC                               ...(1)

Now, ∠ACD = 180° - ACB  ...(Linear pair)

⇒ ∠ACD = 180° - 67°

⇒ ∠ACD = 113°

Thus, in ΔACD,

∠CAD = 180°- ∠ACD + ∠ADC

⇒ ∠CAD = 180° - (113° + 33°)

⇒ ∠CAD = 180° - 146°

⇒ ∠CAD = 34°

Since ∠ADC < ∠CAD, we have

AC < CD                            ...(2)

From (1) and (2), we have

BC < AC < CD

shaalaa.com
  Is there an error in this question or solution?
Chapter 11: Inequalities - Exercise 11 [Page 142]

APPEARS IN

Selina Concise Mathematics [English] Class 9 ICSE
Chapter 11 Inequalities
Exercise 11 | Q 4.1 | Page 142
Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×