Is 3.21 rational or irrational

Find the area of a parallelogram with the given vertices. p(-2, -5), q(9, -5), r(1, 5), s(12, 5)

Estimate the area under the curve f(x) = 16 - x^2 from x = 0 to x = 3 by using three inscribed (under the curve) rectangles. answer to the nearest integer.

50 plz, given the system of equations, match the following items. x + 3 y = 5 x - 3 y = -1 a) x-determinant b) y-determinant c) system determinant match the following to the pictures below.