Answer:
In the figure, by exterior angle property, you have
ACD = A+ B
CBF = A+ C
BAE = B+ C
Adding the above equations, you get
ACD +CBF +BAE = A+ B +A+ C + B+ C
= 2 (A+ B +C)
= 2 180o (angle sum of a )
ACD +CBF +BAE =360o
That is the sum of the exterior angles = four right angles. (360o = 490o)
Step-by-step explanation: