o is the centre of the circle, and lenth of the chood is 8 cm seg op & chord Am If I Cop) -3.cm then find radius of the circle
Answers
Answer:
GIVEN: A circle with centre O, Radius AO = 13 cm, Chord AB = 24 cm
TO FIND : The perpendicular distance of the chord from O. Let it be called OM.
OM is perpendicular to the chord AB.
Perpendicular from the centre O to a chord bisects the chord. So AM = AB/2 = 12 cm
In right triangle AMO , Using Pythagoras’s Theorem,
AO² = AM² + OM²
=> 13² = 12² + OM²
=> 169 = 144 + OM²
=> OM² = 169 - 144 = 25
=> OM = √25 = 5 cm.
Given: AB and AC are two equal chords of a circle with centre O.
OP⊥AB and OQ⊥AC.
To prove: PB=QC
Proof: OP⊥AB
⇒AM=MB .... (perpendicular from centre bisects the chord)....(i)
Similarly, AN=NC....(ii)
But, AB=AC
⇒ 2AB = 2AC
⇒MB=NC ...(iii) ( From (i) and (ii) )
Also, OP=OQ (Radii of the circle)
and OM=ON (Equal chords are equidistant from the centre)
⇒OP−OM=OQ−ON
⇒MP=NQ ....(iv) (From figure)
In ΔMPB and ΔNQC, we have
∠PMB=∠QNC (Each =90∘ )
MB=NC ( From (iii) )
MP=NQ ( From (iv) )
∴ΔPMB≅ΔQNC (SAS)
⇒PB=QC (CPCT)