### Home > GB8I > Chapter 5 Unit 6 > Lesson INT1: 5.1.1 > Problem5-16

5-16.

On graph paper, plot $ABCD$ if $A(–1, 2)$, $B(0, 5)$, $C(2, 5)$, and $D(6, 2)$.   (Desmos)

1. If $ABCD$ is rotated $90º$ counterclockwise ($\circlearrowleft$) about the origin, name the coordinates of the image $A'B'C'D'$.

2. On your graph, reflect $ABCD$ across the $y$-axis to find $A''B''C''D''$. Name the coordinates of $A''$ and $C''$.

3. Calculate the area of $ABCD$. Hint: Divide the figure into rectangles and triangles.

Area of a trapezoid $=\frac{1}{2}(b_{1}+b{_{2}})h$

Complete the tables in the eTool below to plot the points, rotate and reflect the shape.
Click on the link at the right to view full version of the eTool:  (Desmos)