Dear Aspirant

Kepler's three laws of planetary motion can be stated as follows:

1) All planets move about the Sun in elliptical orbits, having the Sun as one of the foci.

2) A radius vector joining any planet to the Sun sweeps out equal areas in equal lengths of time.

3)the square of a planet’s orbital period is proportional to the cube of the semi-major axis of its orbit.

And

girder shape is done when a beams have very high moment of inertia for the same volume of the given material. ... The two horizontal parts (called flanges) of the I beam can bear high bending and shearing stress. That means they do not get twisted and tilted easily. That is why they are used in girders

i hope it will help you

Thank you