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Finding the Fourth Proportional to 981.54, 1,354.59 and 686.70

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Solution

The fourth proportional to 981.54, 1,354.59 and 686.70 is: 947.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    981.54 : 1,354.59 = 686.70 : x
  2. Step 2: Convert to fraction form
    981.54/1,354.59 = 686.70/x
  3. Step 3: Cross multiply
    981.54x = 1,354.59 × 686.70
  4. Step 4: Simplify right side
    981.54x = 930,196.95
  5. Step 5: Solve for x
    x = 930,196.95/981.54
  6. Step 6: Final answer
    x = 947.69

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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.