My sister asked me to let them do a presentation at my house. I didn't want to do it, but it would help her out. When Teresa came to my house and hit me with her sale pitch, I wasn't feeling any of it ...

There are seven types of electromagnetic (EM) waves, which make up the electromagnetic spectrum. Electromagnetic waves are transverse waves, and travel at the speed of light. Different types of ...

The sides of right-angled triangles are labelled opposite, hypotenuse and adjacent. Trigonometry explores the relationship between sides and angles in right-angled triangles. The hypotenuse is the ...