Angle & Triangle Types

Three short rounds. In each round you'll see a few diagrams, and your job is to click every one that matches the named type. The same skill, three different topics.

Section 1 · Angle Types

Five angle categories you should recognise on sight:

• Acute — smaller than 90° (sharp).
• Right — exactly 90° (square corner; marked with a small square).
• Obtuse — between 90° and 180° (blunt).
• Straight — exactly 180° (the rays form a straight line).
• Reflex — bigger than 180° (the arc wraps the long way).

Example — an obtuse 130° angle.

Section 2 · Triangles by Angle

A triangle is classified by its largest angle:

• Acute-angled — every angle is less than 90°.
• Right-angled — exactly one angle is 90° (square marker at one vertex).
• Obtuse-angled — one angle is bigger than 90°.

Section 3 · Triangles by Side

A triangle is also classified by which sides are equal. Tick marks on the sides indicate equality — sides with the same number of ticks are equal.

• Equilateral — all three sides equal (matching ticks on every side).
• Isosceles — exactly two sides equal.
• Scalene — all three sides different.

Example — an equilateral triangle (all sides equal).

Three Sections Sealed