Question

In triangle ABC,AD perpendicular BC.AB=15 cm,AD=12 cm,AC=13 cm.find the length of BC?

Answer 1

Answer:

Step-by-step explanation:

Step 1: by using Pythagoras

On both sides and adding BD + DC = BC

9. + 5 = 14

BC =14 cm

Answer 2

In triangle abc,two right angles are formed

• triangle abd

•triangle adc

☆ in triangle abd

Ab=15cm and ad= 12cm

As we all know that h^2=a^2+b^2

So in first triangle

Ab^2=ad^2+bd^2

.°. 15^2=12^2+bd^2

225=144+bd^2

225-144=bd^2

81=bd^2 {underrooting both the sides}

9cm=bd

☆now in triangle adc

Ad=12cm and ac=13cm

So now h^2=a^2+b^2

.°. ac^2=ad^2+dc^2

13^2=12^2+dc^2

169=144+dc^2

169-144=dc^2

25=dc^2 {underrooting both the sides}

5cm=dc

Now add both the sides

Cb=bd+dc

Cb=(9+5)

Cb=14cm