Ratios, Proportions, Cross-multiplication, and Percent
Definitions and use of ratios, proportions, cross-multiplication, and percent are taught and demonstrated. Students are then given problems – including word problems – to apply what they have learned to real-world situations. This is followed by step-by-step solutions.
The distance between two cities is 60 miles. After going 42 miles, what percentage of the distance has been traveled?
Make a ratio with x over 100. Then solve for x.
42/60 = x/100
60x = 42(100) Cross-multiply
60x = 4200
60x/60 = 4200/60
x = 70 (70%)
PLEASE NOTE: I could only write in this preview box with slanted lines for the fractions, but in the actual lesson, the fractions in this problem are set up with numerators directly over denominators.
Please click on the link for the PREVIEW to see how the problem is actually set up in the lesson. The math is on the left side of the page and the instructions are written on the right side so that the student sees the instructions paired with the math steps.