Proportion and Percent Review

Ex 2 A geometry class consists of 13 males and 16 females. Find the ratio of females to males. Find the ratio of females to the entire class. There are 29 in the class.

Ex 4 The approximate ratio of the circumference (distance around) to diameter (distance across the top) of an oil barrel is inches to 30.5 inches. Express this ratio as a fraction in reduced form. To reduce fraction Math enter enter

Ex 6 Write the ratio as a rate in lowest terms: $3.90 for 6 muffins To reduce fraction Math enter enter

Ex 9 Which of the following pairs of ratios do not form a proportion? Not a proportion Cross Multiply

Ex 4 Set up proportions The area of a set of rectangular pictures is held constant while the length and width may change. If the length is 14 the width is 5, write as a proportion when the width is 6.

Ex 6 Set up & Solve proportions A regional forestry division wanted to estimate the number of deer in a particular national park. They caught and tagged 76 deer and released them back into the park. Later they selected a sample of 225 deer. Of these 225 deer, 15 were tagged. What is the best estimate of the number of deer in the park?

First - Set up & solve the proportion. 2) 3 is to 2 as x is to 18. ____ = ____ 3 2 x 18 Now cross multiply 2x = x =27

4) 16m = 8 16 m= Now Reduce

5) Mr. Jones has taken a survey of college students and found that 40 out of 47 students are liberal arts majors. If a college has 10,827 students, what is the number of students who are liberal arts majors, rounded to the nearest whole number? ____ = _______ First – Set up Your proportion! ,827 x Now cross multiply 47x= 433, x = 9214

The Formula Also called the (Part) Also called the (Whole) or (Total) or (Base)

7. 12 is 80% of what number? 8. Find a number so that 66 2 / 3 % of it is 12. Finding the Base