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Finding the Fourth Proportional to 781.92, 1,078.78 and 502.13

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Solution

The fourth proportional to 781.92, 1,078.78 and 502.13 is: 692.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.92 : 1,078.78 = 502.13 : x
  2. Step 2: Convert to fraction form
    781.92/1,078.78 = 502.13/x
  3. Step 3: Cross multiply
    781.92x = 1,078.78 × 502.13
  4. Step 4: Simplify right side
    781.92x = 541,687.80
  5. Step 5: Solve for x
    x = 541,687.80/781.92
  6. Step 6: Final answer
    x = 692.77

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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.