Question

If a^2 + b^2 + c^2 = 150 and a + b + c = 20, then find the value of 3( ab +bc +ca )

Answer 1

Answer:

In ABC, it is given that D is the midpoint of BC, E is the midpoint of BD and O is the midpoint of AE.

Then BE=

4

1

BC OR OE=

2

1

AE

WE know thet area of triangle =

2

1

h.b

Area of triangle ABC=

2

1

BC(AE)

Area of triangle BOE=

2

1

BE(OE)

Then area of triangleBOE=

8

1

area of triangleABC