Which set of side lengths represents a triangle with 3 lines of reflectional symmetry? (3, 4, 5)
(3, 6, 9)
(5, 5, 5)
(5, 10, 5)

The first and the last set do not represent triangle at all, because the sum of two lengths is equal to the third length:

3 + 6 = 9;

5 + 5 = 10.

The second set represent equilateral triangle, because all sides have the same lenghts. Each equilateral triangle has 3 lines of reflections. These lines are exactly three medians of the triangle (because each median in equilateral triangle is the perpendicular bisector of the base of the triangle and divides the triangle in two congruent right triangles).

correct choice is B - set (5,5,5)

As the bottom answer stated it would be C) (5, 5, 5) Not B.

answer: 42

use a calculator to find that 845/73 = 11.575

the whole part of the answer is 11. multiply this by 73 to get 11*73 = 803.

subtract that result from 845 to get 845 - 803 = 42

d. it is a convex pentagon because it has five sides and none of the sides would extend into the inside of the polygon.

step-by-step explanation: