Question

Polygon abcd has the following vertics: a( -3, 3) b (5, 5) c (5, -4 ), d (-3 -4). caculate the area of the polygon

Answer 1

Analytic geometry (polygon in the coordinate system).

Mark the point on the coordinate system and draw the polygon (attachment).

This is the trapezoid.

The formula of an area of a trapezoid:

$A=\dfrac{a+b}{2}\cdot h$

a, b - the lengths of the parallel sides

h - the height

Substitute:

$a=9,\ b=7,\ h=8\\\\A=\dfrac{9+7}{2}\cdot8=\dfrac{16}{2}\cdot8=8\cdot8=64[u^2]$

$\huge\boxed{A=64u^2}$