Question

Rotate the triangle ABC about vertex C by 120 degrees to form A'B'C' and choose the correct statement from the following:

• A. Perimeter of the triangle increases by 2 times.
• B. Coordinates of B and B' remains the same.
• C. Angle A = Angle A'
• D. Area of ABC is half the Area of A'B'C'.

Answer 1

The correct option is C Angle A = Angle A'

Here, A'B'C' is obtained by rotating ABC by 120 degrees. Since C is at the center of rotation, the rotation leaves its coordinates unchanged.

Therefore, the coordinates of C and C' remain the same.

Perimeters of ABC and A'B'C' remain the same as rotation does not affect their perimeters.

The angle measure does not change after rotation, so angle A is equal to angle A'.

Therefore, option (c) is the correct answer.