Geometry puzzle

1. A line that goes through the circle
5. A solid object with two identical ends and flat sides
10. The distance from the center of the circle to the edge
12. a branch of mathematics concerned with relationships between angles and ratios of lengths
15. v=π × r² × (h/3)
16. The largest arc in a circle
18. triangle with at least two equal sides
19. base x height

1. when one shape is identical to the other shape when it is moved, rotated, or flipped.
2. a2+b2=c2
3. two lines in the same plane that are at an equal distance from each other and never meet.
4. Quadrilateral, Decagon, Dodecagon, Concave polygon
6. two figures having the same shape
7. half of a sphere
8. activity to do during a windy day
9. A line segment connecting two points on a curve
11. rise over run
13. 1:2
14. The size of a surface
17. extends endlessly in both directions