Question

Question No. 12
If BC and OB are
equal to 8 cm and
5 cm
5
respectively.
then find the value of
3AO in cms

Answer 1

Answer:

i think 25 is the correct answer...

Answer 2

Step-by-step explanation:

OB=OC=5cm (Radius of circle)

BC is chord of circle

BC=8cm

BM=MC=4cm ( Perpendicular bisector from centre of circle bisects the chord)

Area of Triangle AOB=1/2*AB*OB

Area of Triangle AOB=1/2*OA*BM

1/2*AB*OB=1/2*OA*BM

AB*5=OA*4

AB/OA=4/5

In Right angled triangle AOB

By using pythagoras theorem

AB^2+OB^2=OA^2

(4/5*OA)^2+25=(OA)^2

16/25*OA^2+25=OA^2

25=OA^2-(16/25)*OA^2

25=9/25*OA^2

Taking square root on both sides

5=3/5*OA

5*5/3=OA

25/3=OA

25=3*OA