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Finding the Fourth Proportional to 781.66, 1,078.32 and 615.61

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Solution

The fourth proportional to 781.66, 1,078.32 and 615.61 is: 849.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.66 : 1,078.32 = 615.61 : x
  2. Step 2: Convert to fraction form
    781.66/1,078.32 = 615.61/x
  3. Step 3: Cross multiply
    781.66x = 1,078.32 × 615.61
  4. Step 4: Simplify right side
    781.66x = 663,824.58
  5. Step 5: Solve for x
    x = 663,824.58/781.66
  6. Step 6: Final answer
    x = 849.25

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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.