The father is 60 years old and his son is half his age. how old was the boy when his father was 4 times his age?

Then 30-20= 10 yrs. old, the boys age when his dad was 40 years old

answer: option a.

step-by-step explanation:

you know that the quadrilateral opqr ( a four sided figure) is inscribed in circle. this means that all its vertices are on the circle.

then, by definition, the opposite angles of the quadrilateral are supplementary, this means that the sum of their measures is 180 degrees.

you can observe in the figure that the angles ∠opq   and the angle ∠orq   are opposite, therefore:

then, can be used to d to calculate the measure of ∠opq

idk

step-by-step explanation: