Given:
m(ar LNM) = 280°
To find:
The value of y.
Solution:
Complete angle = 360°
m(ar LNM) + m(ar LM) = 360°
280° + m(ar LM) = 360°
Subtract 280° from both sides.
280° + m(ar LM) - 280° = 360° - 280°
m(ar LM) = 80°
Inscribed angle is equal to the half of the intercepted arc.
The value of y is 40 degrees.