It was once believed that all of the bodies of the solar system were perfect spheres with absolutely nothing on their surfaces. How did Galileo disprove this notion in the early 1600s?
A.
He used a gyroscope to measure the gravity of Jupiter.

B.
He used a rocket to measure the width of Earth's atmosphere.

C.
He used a spectroscope to observe the light from the Sun.

D.
He used a telescope to observe mountains on the Moon.

The answer is d.

Step-by-step explanation:

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