Solving Ratios and Proportions

Grade 9s have been working on fraction skills lately. Today we worked on solving questions with ratios and proportions.

We used a few strategies: for some questions we looked at creating equivalent fractions by multiplying the numerator and denominator by the same values. If we multiply the denominator 5 by 6 to create 30, we need to multiply the numerator x by 6 to create 2. We can then solve for x.

We also found a strategy of making common numerators, or common denominators. We know that if 2 fractions are equal, if we can make the numerators equal, then we know the denominators will be equal. In this example above, we make the numerators both 70. This leaves us with denominators of 5x and 126 which are both equal as well. We can then solve the equation 5x=126.

We also saw how this skill can help us solve proportions in similar triangles. It was a busy day with lots of solving and working together.