1. The resultant of two forces X and Y will be greatest when the angle between X and Y solve it

greatest when the forces are parallel, the angle between them is 0.

Pls I want the reason why

Thank you for this I appreciate

Like how is it 0

The answer is 0 pls just comply

greatest when the forces are parallel, the angle between them is 0.

Exactly lets all just comply to the answer given:zero