In a cookie recipe, for every 3 cups of flour, 2 teaspoons of vanilla is needed. How many teaspoons are needed for 5 cups of flour

to find this answer we use proportional reasoning.

3 cups of flour:2 teaspoons of vanilla

3:2

if 5 cups of flour are used then we adjust the ratio to keep it proportional

the vanilla is 'x' because we don't know the value (yet)

5:x

then we set it up in an equation and solve

3/2=5/x

2 multiplied by 5 divided by 3 x=3.33

5:3.33

you need 3.33 teaspoons of vanilla for 5 cups of flour