Math puzzle

3. A number that divides another number exactly with no remainder.
4. A mathematical statement showing the equality of two expressions using an equal sign.
7. The total length around a two-dimensional shape.
8. A number greater than 1 that has only two divisors, 1 and itself.
13. The operation of repeated addition of the same number.
14. Formed by two rays meeting at a common point called the vertex.
15. Lines that intersect to form a right angle.
17. A 3D solid figure with six equal square faces.
18. A straight line passing through the center of a circle, touching both sides.
19. An angle measuring exactly 90 degrees.

1. Lines that never meet, no matter how far they are extended.
2. The distance from the center of a circle to any point on the circle.
5. The branch of mathematics that deals with variables and the rules for manipulating them.
6. The perimeter or boundary of a circle.
9. A polygon with four equal sides and four right angles.
10. A shape where all points are equidistant from a central point.
11. The amount of space occupied by a 3D object, measured in cubic units.
12. A polygon with three sides and three angles.
14. The amount of surface covered by a shape, measured in square units.
16. A number which, when multiplied by itself, gives the original number.