If the center of rotation is a point outside the triangle, then this would mean that there would be quadrant shift (revolution) of the whole triangle itself. Hence this would mean that the resulting triangle will not touch the pre-image at any point at all.

If the center of rotation is a point on the perimeter of the triangle, this would also result in a quadrant shift (revolution) or movement of the triangle.

Now if the center of rotation is a point inside the triangle, then this would be a simple rotation on its own quadrant hence the resulting image will touch the pre-image at more than one point. Hence the correct points are:

point D and point E

8 0

2 years ago

What is the measure of Angle D F E?

sweet-ann [11.9K]

Given:

Given that the measure of the exterior angle F is 142°

We need to determine the measure of ∠DFE

Measure of ∠DFE:

The ∠DFE and the exterior angle F are linear pairs.

Thus, the linear pair of angles add up to 180°

Hence, we have;

$\angle DFE+142^{\circ}=180^{\circ}$

Subtracting both sides of the equation by 142, we get;

$\angle DFE=38^{\circ}$

Hence, the measure of ∠DFE is 38°

Thus, Option a is the correct answer.

3 0

2 years ago