P, Q and R are three points on the circumference of a circle such that QR is a diameter and PQ = PR. If the radius of the circle is 7 cm, then the length of PQ is:
Answer & explanation
Correct answer: option 4
We have,
The radius of the circle = 7 cm.
We know that,
∠QPR = 90° ( angle in a semicircle opposite to diameter is always 90°)
So ∆PQR is a right angle triangle
PQ = QR/√2 (In an isosceles right triangle the smaller side is (1/√2) of hypotenuse)
= PQ = 14/√2
= PQ = 7√2