CheerMath

Grade 7 Proportions Practice

Check & Solve Proportions

Check and solve! Test a proportion several ways, write cross-product equations, solve with cross multiplication, complete proportion tables, and use proportions in real situations.

Also known as Class 7 maths — the same topics, whether your school calls it grade, class or year.

Sign up for free

Sample questions

A few samples from this topic — try one, then show the answer.

  1. Solve Proportions with Cross Multiplication

    Solve for m: 1421  =  m3\frac{14}{21} \; = \; \frac{m}{3}
    Show answer
    Answer:
    2

  2. Review Equivalent Ratios, Simplifying & Cross Products

    A student checks whether 68=912\frac{6}{8} = \frac{9}{12} by computing cross products. Which calculation is correct?
    • 6×86 \times 8 and 9×129 \times 12
    • 6×126 \times 12 and 8×98 \times 9
    • 8×128 \times 12 and 6×96 \times 9
    • 6  +  126 \; + \; 12 and 8  +  98 \; + \; 9
    Show answer
    Answer:
    6×126 \times 12 and 8×98 \times 9

  3. Solve Proportions in Real-Life Situations

    Making 10 litres of juice needs 11 oranges. How many oranges do you need for 20 litres?
    • 22
    • 33
    • 21
    • 11
    Show answer
    Answer:
    22

Want more like these? Try a round — no sign-up

A worked example

Solve for m: 1421  =  m3\frac{14}{21} \; = \; \frac{m}{3}
  1. We need to solve the proportion: 1421  =  m3\frac{14}{21} \; = \; \frac{m}{3}
  2. To solve a proportion, cross-multiply: multiply each numerator by the opposite denominator.\\Equal fractions always have equal cross products:14  ×  3  =  21  ×  m\\ 14 \; \times \; 3 \; = \; 21 \; \times \; m \\[4pt]42  =  \; = \;21  ×  m\; \times \; m
  3. Divide both sides by 21 to get the unknown by itself:4221  =  \\ \frac{42}{21} \; = \;2
  4. The answer is 2.\\Check by substituting back: 1421  =  23\frac{14}{21} \; = \; \frac{2}{3} \\14  ×  \; \times \;3  =  \; = \;42 and 21  ×  \; \times \;2  =  \; = \;42. Both cross products are equal ✓\checkmark

More Grade 7 topics