Draw 90 degree first then draw 60degree on the same diagram then bisect those two angles you will get 75degrees. I don't no about 70 degrees

Angles can be effectively 'added' by constructing them so they share a side. This is shown in Constructing the sum of angles.

As an example, by first constructing a 30° angle and then a 45° angle, you will get a 75° angle. The table below shows some angles that can be obtained by summing simpler ones in various ways

To make Combine angles

75° 30° + 45°

105° 45° + 60°

120° 30° + 90° or 60° + 60°

135° 90° + 45°

150° 60° + 90°