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Finding the Fourth Proportional to 778.34, 1,073.78 and 515.90

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Solution

The fourth proportional to 778.34, 1,073.78 and 515.90 is: 711.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    778.34 : 1,073.78 = 515.90 : x
  2. Step 2: Convert to fraction form
    778.34/1,073.78 = 515.90/x
  3. Step 3: Cross multiply
    778.34x = 1,073.78 × 515.90
  4. Step 4: Simplify right side
    778.34x = 553,955.15
  5. Step 5: Solve for x
    x = 553,955.15/778.34
  6. Step 6: Final answer
    x = 711.72

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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.