Sect. 1.5 Formulas, Models & Geometry (Lite!)

Sect. 1.5Formulas, Models & Geometry (Lite!) • Types of Formulas • Solving Formulas • (Rearranging) • Mathematical Models 1.5

You already know the Rules 1.5

Types of Formulas • D = R·T Distance = Rate x Time • Economics: • C = A·Utotal_Cost= Amount x Unit_cost • I = P·r·tsimple_Interest = Principal x Rate x Time • A = P + P·r·tAccumulated_value = Principal + interest • S = C + C·mSelling_price = wholesale_Cost + Markup • Geometry: Squares Rectangles Circles • Perimeters P=4s P=2w+2l C=πd (circumference) • Areas A=s2 A=w·l A= π r2 • Cubes Blocks Spheres • VolumesV=s3 V=w·l·h V= (4/3)π r3 • Angles In a triangle 180° = a + b + c 1.5

General Approach to Solving Formulas 1.5

Solving Formulas – 3 Variables • Pick one of the variables and rearrange the formula (using algebraic properties) to isolate it 1.5

Simple Interest – 4 variables • Only two terms in this formula 1.5

Formulas with Complex Terms • When a factor is a sum … 1.5

Isolating a Common Factor • The Law of Distribution works both ways:a(b + c) = ab + ac and ab + ac = a(b + c) 1.5

Mathematical Models • To represent or approximate real-world situations • Use the Body Mass Index formula to find someone’s approximate weight. Her BMI is 42.2 and height is 5’9” • First, solve the formula for W, then substitute, simplify and solve. (board) 1.5

Next? • Now on to 1.6 Properties of Exponents 1.5

Sect. 1.5 Formulas, Models & Geometry (Lite!)