What evidence supports the presence of a supermassive black hole at the center of the Milky Way?

In a model of the solar system, the Earth has diameter of is 1 cm and the diameter of Jupiter is 11cm. If the diameter of the Earth is 12,742km and diameter of Jupiter is 139,820km. The average scale factor of the model is:

In a scale model of solar system, the scale factor is 10^{-3}cm/km. The diameter of the Sun is 1,391,000km. The diameter of the Sun in the model is:

The average of following scale factors 10^{-3}cm/km, 10^{-4}cm/km, 10^{-5}cm/km is:

Calculate the following:

The diameter of the Sun is 1,391,000km. The predicted diameter of the Sun using a scale model is 1,377,090km. The percentage error in the prediction is:

What is value when the base is 10 and the exponent is 0?

The distance from the sun to Jupiter in AU

Write the number  -2 x 10⁸  in ordinary decimal form.

The distance to the Andromeda Galaxy in light-years.