Explain two dimensional co-ordinate systems

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

Julie was able to walk 16 km through the zoo in 6 hours. how long will it take her to walk 24 km through the zoo?

In chemistry,n molecules of an ideal gas have pressure, volume, and tempersture that stand inthe following relation, where r is constant. solve the equation for n,the number of molecules. pv=nrt