Angle Practice Studio.
Estimate angles, test geometric relationships, and reveal answers. Toggle a virtual protractor to practice manual reading.
Single Angle Practice
Estimate the angle type and magnitude, then click to reveal answers.
Types of Angles & Relationships
A quick reference for angle classifications, ranges, and geometric properties.
Acute Angle
An angle strictly between 0° and 90°. Common examples include roof pitches, equilateral triangle corners (60°), and scissor blades.
Right Angle
An angle of exactly 90° (π/2 radians), forming perpendicular lines found in door frames, books, and square corners.
Obtuse Angle
An angle greater than 90° but less than 180°. Found in reclined seats, wide roof gables, and hockey stick shafts.
Straight Angle
An angle of exactly 180° (π radians). The two arms point in opposite directions to form a continuous straight line.
Reflex Angle
An angle strictly greater than 180° and less than 360°. Represents the major outer arc measured by a 360° full-circle protractor.
Complete Angle (360°)
A full 360° rotation where the ray circles completely back to the baseline (equal to 1 full turn or 2π radians).
Angle Pairs
• Complementary: Two angles that add up to 90°.
• Supplementary: Two angles that add up to 180°.
Conjugate Angles
Two angles that add up to 360° (a + b = 360°). Divided into four 90° quadrants: Q I (0–90°), Q II (90–180°), Q III (180–270°), and Q IV (270–360°).