This tutorial discusses the differences and similarities between similar and congruent figures and triangles.

This tutorial discusses how trigonometry uses ratios of sides in similar triangles and that is why trig works no matter what size triangle is used.

This lesson works though three examples of solving problems using similar triangles.

This tutorial shows how to change from degrees to radians to gradients in some common scientific calculators. The tutorial also shows the difference between DAL logic and non-DAL logic calculators. Two examples show how to evaluate the sin 32° and cos^-1(0.3907) or the inverse cos of 0.3907.