Question

Fill in the blanks
18. A triangle has ………… altitudes
19. A regular pentagon has …… lines of symmetry.
20. Number of edges for a cuboid is ………….
21. Angle which is equal to its supplement is ……
22. In a triangle, a line which connects a vertex to the midpoint of its opposite side is called ……....

Answer 1

Answer:

18-1

19-5

20-4

21-90°

22-perpendicular line

hope this helps you

Answer 2

1) 3

Since all triangles have three vertices and three opposite sides, all triangles have three altitudes.

2) 5

The number of lines of symmetry in a regular polygon is equal to the number of sides.

3) 12

By Euler's formula the numbers of faces F, of vertices V, and of edges E of any convex polyhedron are related by the formula F + V = E + 2. In the case of a cuboid this gives 6 + 8 = 12 + 2; that is, like a cube, a cuboid has 6 faces, 8 vertices, and 12 edges.

4) 90°

180° - 90° = 90°

5) A median

In geometry, a median of a triangle is a line segment joining a vertex to the midpoint of the opposite side, thus bisecting that side. Every triangle has exactly three medians, one from each vertex, and they all intersect each other at the triangle's centroid.