Question

In Fig. 4.140, ∠ABC= 90° and BD⊥AC. If AB = 5.7 cm, BD = 3.8 cm and CD = 5.4 cm, find BC.

Answer 1

BC = 6.6 cm

Step-by-step explanation:

Given:

Here ∠ABC= 90° and BD⊥AC.

AB = 5.7 cm, BD = 3.8 cm and CD = 5.4 cm.

As it is given that BD⊥AC then ∠BDC = 90°

In right angled triangle BDC

Using Pythagoras theorem

$BC^2=BD^2+CD^2$

$BC^2= (3.8)^2 + (5.4)^2$

$BC^2= 14.44 + 29.16$

$BC^2=43.6$

$BC = \sqrt{43.6}$

BC = 6.6 cm