Mathematics

In the diagram above, the value of angles b + c is

In the diagram above, the value of angles b + c is
  • A.
    180o
  • B.
    90o
  • C.
    45o
  • D.
    ao
  • E.
    do
Correct Answer: Option A
Explanation

a + c + d – 180o[sum of angles in triangle]
x = a[vertical opp. ∠s]
y + x + d = 180o[sum of ∠s in a Δ]
y + a + d = 180o
y + a + d = a + c + d
y = c
but b + y = 180o [sum of ∠s on a straight line ]
b + c = 180o; Ans = A = 180o