April 12, 2010 Math 201 OBJECTIVE: Students will be able to evaluate formulas for given input values (circumference, area, volume, distance, temperature, interest, etc.) AIM: What are the two steps that are common to evaluating every formula? STANDARDS: 6.A.6 PRIOR KNOWLEDGE: Evaluate the expressions: n + 5, when n = 7 2a -3, when a = 6 2y/8, when y = 4

Mini Lesson: Formulas – rules or equations that state a mathematical relationship between two or more quantities Example: Find the area of a circle with a radius that is 3 cm in length The formula for the area of a circle = πr2 We can follow 2 steps that are common to evaluating any formula: 1. Rewrite the formula using substitution 2. Do the math according to the order of operations

= π(32) 1. Rewrite the formula using substitution A = πr2 2. Do the math according to the order of operations = 9π sq cm

Example: Ronnie’s family drove from their home to Playland Amusement Park. Their average speed was 40 miles per hour. The trip took 1.5 hours. What is the distance from Ronnie’s home to Playland? The formula for distance is d = rt d stands for distance r stands for the rate of speed t stands for the amount of time the trip takes

Write the formula d = rt Then follow our steps: 1. Substitute the values into the formula r = 40 and t = 1.5 d = rt = (40)(1.5) 2. Do the math (40)(1.5) = 60 So the distance from Ronnie’s home to Playland is 60 miles