Question

rotate triangle def 90 degrees counterclockwise around point e. plot point d. you can use the right - angle tool to help you.

Explanation:

Step1: Recall rotation rule

For a 90 - degree counter - clockwise rotation around a point $(a,b)$ of a point $(x,y)$, the new point $(x',y')$ is given by the transformation $(x - a,y - b)\to-(y - b,x - a)$ and then adding back the coordinates of the center of rotation. In a grid - based system, we can also use geometric properties. If we consider the vector from point $E$ to point $D$, we need to rotate this vector 90 degrees counter - clockwise.

Step2: Analyze grid distances

Count the horizontal and vertical distances from point $E$ to point $D$. Let's assume the grid has unit squares. Then, for a 90 - degree counter - clockwise rotation, the horizontal distance becomes the vertical distance (with a sign change) and the vertical distance becomes the horizontal distance.

Step3: Plot the new point

Based on the above - mentioned rotation rules and grid analysis, plot the new point $D'$.

Since no coordinates are given, we can't provide a numerical answer. But the general method to plot $D'$ is as described above.

Answer:

Plot the new point $D'$ according to the 90 - degree counter - clockwise rotation rules around point $E$ using grid distances and vector rotation concepts.