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Finding the Fourth Proportional to 781.34, 1,078.72 and 545.70

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Solution

The fourth proportional to 781.34, 1,078.72 and 545.70 is: 753.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.34 : 1,078.72 = 545.70 : x
  2. Step 2: Convert to fraction form
    781.34/1,078.72 = 545.70/x
  3. Step 3: Cross multiply
    781.34x = 1,078.72 × 545.70
  4. Step 4: Simplify right side
    781.34x = 588,657.50
  5. Step 5: Solve for x
    x = 588,657.50/781.34
  6. Step 6: Final answer
    x = 753.39

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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.