prove that the difference between any two sides of a triangle is less than its third side
Answers
Answered by
2
Hope it is helpful for you.
Have a great day ahead.
THANK YOU ❤
Attachments:
Answered by
13
━━━━━━━━━━━━━━━━━━━━━━━━━
prove that the difference between any two sides of a triangle is less than its third side
━━━━━━━━━━━━━━━━━━━━━━━━━
A ∆ABC.
(i)AC - AB < BC,
(ii)BC - AC < AB,
(iii)BC - AB < AC.
Let AC > AB. Then, along AC,set off AD = AB.Join BD.
AB = AD⇒ ∠1 = ∠2.⠀⠀⠀⠀⠀⠀⠀....(i)
Side CD of ∆BCD has been produced to A.
∴ ∠2 > ∠4⠀⠀⠀⠀...(ii) [∴ ext.angle > each int.opp angle]
Side AD of ∆ABD has been produced to C.
∴ ∠3 > ∠1⠀⠀⠀⠀....(iii) [ext.angle > each int.opp angle]
⇒∠3 > ∠2⠀⠀⠀⠀...(iv) [using (i)].
From (ii) and (iv),we get ∠3 > ∠4 ⇒ ∠4 < ∠3.
Now,∠4 < ∠3
⇒CD < BC
⇒AD - AD < BC
⇒AC-AB < BC⠀⠀[∴AD = AD].
Hence,AC-AB < BC.
Similarly,BC - AC < AB and BC - AB < AC.
━━━━━━━━━━━━━━━━━━━━━━━━━
Similar questions