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Finding the Fourth Proportional to 1,218.67, 1,681.74 and 721.36

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Solution

The fourth proportional to 1,218.67, 1,681.74 and 721.36 is: 995.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,218.67 : 1,681.74 = 721.36 : x
  2. Step 2: Convert to fraction form
    1,218.67/1,681.74 = 721.36/x
  3. Step 3: Cross multiply
    1,218.67x = 1,681.74 × 721.36
  4. Step 4: Simplify right side
    1,218.67x = 1,213,139.97
  5. Step 5: Solve for x
    x = 1,213,139.97/1,218.67
  6. Step 6: Final answer
    x = 995.46

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.