an angle measures exactly ninety degrees
An angle is 90 degrees if and only if it is a right angle.
A right angle
The corner of a square measures 90 degrees which is a right angle.
An angle which measures exactly 90 degrees is called a "right" angle. (One measuring less than 90 is 'acute', and one measuring more than 90 degrees is 'obtuse'.)
An angle that measures to precisely 90o is called a right angle.
Obtuse. Any angle measuring greater than 90 degrees but less than 180 is considered obtuse. An acute angle is any angle measuring between 0 and 90 degrees. A right angle is an angle measuring exactly 90 degrees while a straight angle measures exactly 180 degrees.
Well, it doesn't exactly have "an angle that measures 45 and 90 degrees". It has one angle that measures 45 degrees, and another angle that measures 90 degrees. That's an isosceles right triangle. The third angle is also 45 degrees, and the length of each leg is 70.7% of the length of the hypotenuse. .
All four are 90 degrees
a right angle measures 90 degrees