Question

I know solve 13
but i want steps​

Answer 1

Explanation:

In triangle ABD,

ang.ABD=90°

AB=9 cm

AD=15 cm

Now,

Using Pythagoras theorem,

AD2=AB2+BD2(2=square)

or,152=92+BD2

or,225=81+BD2

or,225-81=BD2

or,144=BD2

or,BD=12 cm

Then,

In triangle CBD,

CD=5 cm

BD=12 cm

BC=?

Now,

Using Pythagoras theorem,

BC2=CD2+BD2

or,BC2=52+122

or,BC2=25+144

or,BC2=169

or,BC=13 cm

Answer 2

From Pythagorean theorem in ADB triangle
AB^2+BD^2=AD^2
9^2+BD^2=15^2
BD=12

From Pythagorean theorem in BCD triangle
CD^2+BD^2=BC^2
BC^2=5^2+12^2
BC=13