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Finding the Fourth Proportional to 778.50, 1,073.45 and 498.78

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Solution

The fourth proportional to 778.50, 1,073.45 and 498.78 is: 687.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    778.50 : 1,073.45 = 498.78 : x
  2. Step 2: Convert to fraction form
    778.50/1,073.45 = 498.78/x
  3. Step 3: Cross multiply
    778.50x = 1,073.45 × 498.78
  4. Step 4: Simplify right side
    778.50x = 535,416.64
  5. Step 5: Solve for x
    x = 535,416.64/778.50
  6. Step 6: Final answer
    x = 687.75

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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.