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Finding the Fourth Proportional to 978.33, 1,349.85 and 715.89

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Solution

The fourth proportional to 978.33, 1,349.85 and 715.89 is: 987.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.33 : 1,349.85 = 715.89 : x
  2. Step 2: Convert to fraction form
    978.33/1,349.85 = 715.89/x
  3. Step 3: Cross multiply
    978.33x = 1,349.85 × 715.89
  4. Step 4: Simplify right side
    978.33x = 966,344.12
  5. Step 5: Solve for x
    x = 966,344.12/978.33
  6. Step 6: Final answer
    x = 987.75

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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.