# vs.eyeandcontacts.com

## Shape and Properties of Shape Terms

Arc: A part of the circumference of a circle.

Chord: A straight line joining any two points on the circumference of a circle.

Circle: A shape bounded by a continuous line which is always the same distance from the centre.

Circumference: The distance around the outer edge of a circle.

Cube: A solid shape with six square faces which are all equal in size.

Diameter: A chord that passes through the centre of a circle.

Equilateral triangle: A triangle that has three equal sides and three equal angles.

Hypotenuse: The longest side in a right-angled triangle. The hypotenuse is always opposite the right angle.

Isosceles triangle: A triangle that has two equal sides and two equal angles.

Line segment: A part of a straight line.

Parallelogram: A four-sided shape whose opposite sides are equal and parallel.

Perpendicular: At right angles.

Pythagoras’ theorem: In any right angled triangle, the area of the square on the hypotenuse is equal to the sum of the areas of the squares on the other two sides.

Radius: The distance from the centre of a circle to any point on its circumference. Half the length of the diameter.

Right angled triangle: A triangle that has an interior angle of 90°.

Scalene triangle: A triangle where no two sides or angles are equal in measure.

Sector: A part of a circle enclosed by an arc and two radii.

Segment: A part of a circle cut off by a chord.

Tangent: A straight line that touches a circle at one point only.

Triangle: A polygon with 3 angles and 3 sides.

Vertical: At right angles to the horizon.