Question

Prove that ABC is right angled triangle
when the length of its sides are given to be
9 cm, 12 cm and 15 cm.​

Answer 1

Step-by-step explanation:

Using apollonies theorem

3(AB

2

+BC

2

+AC

2

)=4(AD

2

+BE

2

+CF

2

)

AB=9cm, BC=12cm, CA=15cm

AD, BE, CF are medians

⇒AD

2

+BE

2

+CF

2

=

4

3

(AB

2

+BC

2

+AC

2

)

=

4

3

[(19)

2

+(12)

2

+(15)

2 ]

= 43

[81+144+225]

= 43×450

=337.5cm.