What angle describe both gibbous phases of waxing and waning?

Answer 1

With the earth at the vertex of the angle, the angle between the sun and moon

is between 90 and 180 degrees during the gibbous phases.

Answer 2

An angle of approximately 135 degrees is typically used to describe both gibbous phases of the Moon during its waxing and waning stages. The waxing gibbous phase occurs when the Moon is more than half but not fully illuminated, and the waning gibbous phase occurs when the Moon is more than half but not fully darkened.