Question

exploring rotations
explore the properties of rotation by following these steps.

1. press rotate to perform a rotation of △abc about point p.
2. make a conjecture:

what do you think is the measure of the angle of rotation? □□□°
check

Explanation:

Step1: Observe the orientation change

Without additional information like angle - measurement tools or reference lines, we assume a common rotation case. If no other hints, a 90 - degree or 180 - degree rotation is likely. But from the general appearance of the triangles' orientation change, if we consider the most basic non - zero rotation, we can start with a 90 - degree rotation assumption.
Let's assume a counter - clockwise rotation (since no direction is specified).
We can use the fact that in a 90 - degree rotation, the perpendicular relationship between corresponding sides can be observed (if applicable).

Step2: Analyze the figure

Looking at the relative positions of $\triangle ABC$ and $\triangle A'B'C'$, we can see that the orientation has changed in a way that is consistent with a 90 - degree rotation.

Answer:

90