In the diagram, NR is a diameter, ∠MNR = x° ...
In the diagram, NR is a diameter, ∠MNR = x° and, ∠SRN = (5x + 20)°. Find the value of 2x.
A.
420
B.
350
C.
200
D.
900
Correct answer is B
∠RMN = 90° (angles in a semicircle is a right angle)
∠SRN = ∠RMN + ∠MNR (ext. angle of a ∆ is equal to the sum of two opp. int. angles)
⇒ 5x + 20 = 90 + x
⇒ 5x - x = 90 - 20
⇒ 4x = 70
x = 704
= 17.4°
therefore, 2x = 2×17.5 = 35°