Question

find the length of BC in the given figure ​

Answer 1

Answer:

OC=9cm this is the answer.

Step-by-step explanation:

In triangle AOB,

angle AOB=90°.......(angles in linear pair)

by Pythagoras theorem,

AB²=AO²+OB²

13²=AO²+5²

169=AO²+25

169-25=AO²

144=AO²

12=AO ........(taking square root to both side)

AO=12cm

In triangle AOC,

angle AOC=90°.......(Given)

by Pythagoras theorem,

AC²=AO²+OC²

15²=12²+OC²

225=144+OC²

225-144=OC²

81=OC²

9=OC......(Taking square root to both side)

OC=9cm

hope it will help you

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Answer 2

Step-by-step explanation:

In triangle AOB.

5² + (AO)² = 13². ( by Pythagoras theorem)

(AO)² = 13² - 5²

(AO)² = 169 - 25

(AO)² = 144

AO = √144

AO = 12 cm. ____(I)

Now , In traingle AOC

(AO)² + (OC)² = (AC)². ( by Pythagoras theorem)

(12)² + (OC)² = (15)². {from (I) }

(OC)² = 15² - 12²

(OC)² = 225 - 144

(OC)² = 81

OC = √81

OC = 9. (II)

So , BC = BO + OC

BC = 5 + 9. {from given and (II) }

BC = 14 cm

Ans. BC = 14cm

Hope it's help you.