Triangles can be sorted by their sides. Equilateral triangles have three equal sides, isosceles triangles have two and scalene triangles have none. A right triangle has one right angle.
Quadrilaterals are sorted by parallel sides and angles. A parallelogram has two pairs of parallel sides. A rectangle is a parallelogram with four right angles. A trapezoid has exactly one pair of parallel sides. Perpendicular lines meet at a right angle.
Worked example
Which triangle has exactly two equal sides?
- Three equal sides is equilateral.
- Two equal sides is isosceles.
Answer:an isosceles triangle
Key words
- parallel
- lines that never meet
- perpendicular
- lines that meet at a right angle
- isosceles
- a triangle with two equal sides
Practise this
New questions every time.
Common Core-referenced: 4.G.A.2