Question

.
The length of perpendicular AD
from the apex of a triangle is 6cm.
and angle A is less than 90°. If
BC = 18 cms. and AC = 10cms,
then what will be the length of
side AB?
(1) 8 cm. (2) 9 cm.
(3) 11 cm
(4) None of these​

Answer 1

3) 11 cm answer thañks for

Answer 2

Step-by-step explanation:

As

AD is drawn perpendicular to BC in right angled

ΔABC, it is apparent that ΔABC is right angled at ∠A.

As can be seen ∠B is common in ΔABC as well as ΔDBA (here we have written two triangles this way as ∠A=∠D, ∠B=∠B and ∠C=∠BAD) - as both are right angled (obviously third angles too would be equal) and therefore we have

ΔABC≈ΔDBA and hence

BC/AB=AB/BD=AC/AD

therefore, we have

BC/AB=AB/BD or

AB²=BC×BD=9×4=36

Hence

AB= 6cm