A right angle is equal to how many radians?

A right angle is equal to how many radians?

• A. π/2
• B. π
• C. π/3
• D. π/6

Answer: (A)

A right angle is 90 degrees, which is one quarter of a full rotation. A full circle is 2π radians, so a quarter of that is (1/4)·2π = π/2 radians. That’s why the right angle equals π/2. The other options correspond to 180 degrees (π radians), 60 degrees (π/3), or 30 degrees (π/6), which are not a right angle.

A right angle is 90 degrees, which is one quarter of a full rotation. A full circle is 2π radians, so a quarter of that is (1/4)·2π = π/2 radians. That’s why the right angle equals π/2. The other options correspond to 180 degrees (π radians), 60 degrees (π/3), or 30 degrees (π/6), which are not a right angle.