1. PQR is an equilateral triangle formed by 3 diagonals of the cube. Therefore, it would be 60 degrees. 2. An angle which measures less than 90° is called an acute angle. The measure between 0° to 90°. In the picture below, the angle formed by the intersection of PQ and QR at Q forms an angle PQR which measures 45°. Thus, PQR is called an acute angle.
