Calculating Velocity when Stuntman Jumps from 1.25m Height

[Delta2]

But, If I think of hypotenuse then, there is force

Yes there is force along the hypotenuse, there is a component of the gravitational force along that way. But we usually talk about this component when we have an inclined plane, here we have a different case, and as I told you before the trajectory of the cyclist is not along the hypotenuse.