Answer:
Given- O is the centre of a circle in which an equilateral ΔPQR has been inscribed.
To find out- ∠QOR=?
Solution- The points P, Q & R are on the circumference of the circle since ΔPQR has been inscribed in the circle. Now the chord QR subtends ∠QOR to the centre O and ∠QPR to the circumference at P.
∴ By rule, ∠QOR=2∠QPR.........(i).
Now PQR is an equilateral Δ. Each of its angle is 60
o
. i.e ∠QPR=60
o
.
So, from (i), ∠QOR=2∠QPR=2×60
o
=120
o
.
Ans- Option B.
solution
