 Ratio: is the comparison of two numbers by division  Ratio of two numbers can be shown like this; a to b, a:b, or a/b  Proportion: equation that says two ratios are equal  To solve a proportion, you have to cross multiply

 If to polygons are similar it means that their corresponding angles are congruent and their corresponding side lengths are proportional,  Same shape, different size  Scale factor: is the ratio of two corresponding lengths in two similar figures, it shows how much a figure has been enlarged or reduced

 Indirect measure: method that uses formulas, similar figures and/or proportions to measure any object

 Right triangle altitude proportionally theorem: the altitude to the hypotenuse of a right triangle, creates two triangles that are similar to the original triangle and to each other  Proportions can be used in real life when you have 20ft of rope to cross a river, and you need to know how wide the river is, you can use proportions to find out if you have enough rope

 A trigonometric ratios is a ratio of two sides of a right triangle  SOH CAH TOA  Sin= opposite/hypotenuse  Cos= adjacent/hypotenuse  Tan= opposite/adjacent To solve a triangle is to find out all the lengths of the sides and the measures of the angles

 The trigonometric ratios are used to find lengths but you can use the inverse to find the measure of angles  Cos-1(adjacent/hypotenuse)=angle  Tan-1(opposite/adjacent)=angle  Sin-1(opposite/hypotenuse)=angle

 Angle of elevation: the angle made with the horizontal looking up  Angle of depression: the angle from the horizontal down to an object below