The justification for the worth of a+b being equivalent to d is on the grounds that contiguous points are strengthening.

Most importantly, it ought to be noticed that a triangle has three sides and the number of points in the triangle will be equivalent to 180°.

Subsequently, in view of the data given in the inquiry, the arrangement will go in this way:

a + b + c = 180°

Note that c + d = 180° since adjoining points are beneficial.

Subsequently, a + b + c = c + d

Gather like terms

a + b + c - c = d

a + b = d

Subsequently, the condition has been demonstrated and showed that a + b = d.