brahmagupta’s mathematical discoveries and work came about while studying a branch of science. what was he studying? psychology economics astronomy geology

What point is the projection of q on a) r b) s c) t

Me complete this proof! prove that a quadrilateral is a square. me with the steps for this proof.

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?