Which of the following tools is not needed to construct a segment bisector?
a. compass
b. straightedge
c. pencil
d. protractor

How many different three-digit numbers can be formed using the digits 1 comma 2 comma 9 comma 6 comma 4 comma 3 comma and 8 without repetition? for example, 664 is not allowed.

Which steps could be part of the process in algebraically solving the system of equations, y+5x=x^2+10 and y=4x-10

The pyraminx is a rubik's cube-type toy in the shape of a tetrahedron. the pyraminx shown below has edges 15\,\text{cm}15cm long and vertical height h=12.2\,\text{cm}h=12.2cm. the triangle drawn with dashed lines is a right triangle. what is the distance rr? round your answer to the nearest tenth.