Maths

5. A point, line or plane that divides a line, an angle or a solid shape into two equal parts.
6. In algebra, describing an expression or equation of degree one. Example: 2x + 3y = 7 is a ... equation.
7. In relation to a circle, the distance from the centre to any point on the circle. Similarly, in relation to a sphere, the distance from the centre to any point on the sphere.
8. Any of the positive or negative whole numbers and zero.
12. A line or plane that is at right angles to another line or plane.
13. The distance around a circle (its perimeter).
15. A mathematical form expressed symbolically.
17. A quantity that can take on a range of values, often denoted by a letter, x, y, z, t, … etc.
18. The region within a circle bounded by two radii and one of the arcs they cut off.
19. Often used synonymously with average.
21. An instrument for measuring angles.

1. In the notation of common fractions, the number written on the top – the dividend (the part that is divided). In the fraction ⅔, the ... is 2.
2. Describing a expression of the form ax2 + bx + c where a, b and c are real numbers.
3. Any of the chords of a circle or sphere that pass through the centre.
4. The length of the boundary of a closed figure.
9. A mathematical statement showing that two expressions are equal. The expressions are linked with the symbol =
10. A fraction expressed as the number of parts per hundred
11. A straight line segment joining two points on a circle or other curve.
12. The ratio of the circumference of a circle to the length of its diameter is a constant called...
14. Also known as index, a number, positioned above and to the right of another (the base), indicating repeated multiplication when the exponent is a positive integer.
16. The part of a line between two points. Within a circle, the region bound by an arc and the chord joining its two end points.
20. A portion of a curve. Often used for a portion of a circle.