For geometry:(

please help, will give brainist!!!

Prove that quadrilateral is a rhombus.

The ratio of the measures of the three angles in a triangle is 2: 9: 4. find the measures of the angels

Brainliest ! which of the coordinates are not of th vertices of the feasible region for the system of inequalities y≤4,,x≤5,x+y> 6 a(2,4) b(0,6) c(5,4) d(5,1)