Help don't answer if you don't know

48

Step-by-step explanation:

Since it's a right angle, it's automadically 90 degrees so you just have to add 23+ 19 and subtract from 90.

23 + 19 = 42

90 - 42 = 48

no not all of them.

step-by-step explanation:

some of them have a square base.

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