TYPES OF TRIANGLES
A triangle with all sides different lengths.
What is a scalene triangle?
This triangle has all angles less than 90°.
What is an acute triangle?
A quadrilateral with both pairs of opposite sides parallel.
What is a parallelogram?
Explain why a square is always a rectangle.
A square has four right angles and opposite sides parallel, which define a rectangle.
A 3D shape with two circular bases and one curved surface.
What is a cylinder?
A triangle with two equal sides.
What is an isosceles triangle?
Explain why an equilateral triangle is also an acute triangle.
Because all its angles are 60°, which are less than 90°.
A quadrilateral with four equal sides but angles are not necessarily 90°.
What is a rhombus?
Explain why a rectangle is not always a square.
A rectangle does not need four equal sides.
A 3D shape with one circular base and an apex.
What is a cone?
A triangle with three equal sides and three equal angles.
What is an equilateral triangle?
Explain why a triangle cannot have two obtuse angles.
Two angles larger than 90° would make the sum greater than 180°, which is impossible for triangles.
A quadrilateral with four right angles
What is a rectangle?
Which quadrilateral has no parallel sides?
An irregular quadrilateral
A 3D shape with flat faces, straight edges, and no curved surfaces.
What is a prism?
A triangle with one angle greater than 90°.
What is an obtuse triangle?
Which triangle category is based on angles, not sides: equilateral, scalene, isosceles, or right?
Right triangle.
A quadrilateral with one pair of parallel sides.
What is a trapezoid?
Which shape has four sides the same length but no right angles?
A rhombus.
A 3D shape with triangular faces that meet at an apex and one base.
What is a pyramid?
A triangle with one right angle.
What is a right triangle?
Explain why a triangle with side lengths 4 cm, 4 cm, and 6 cm is not scalene.
Because it has two equal sides, so it is isosceles.
A quadrilateral with four equal sides and four right angles.
What is a square?
Explain why a trapezoid is not a parallelogram.
A trapezoid has only one pair of parallel sides, but a parallelogram has two pairs.
A 3D shape with no edges, no faces, and one curved surface.
What is a sphere?