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Finding the Fourth Proportional to 517.18, 774.54 and 420.78

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Solution

The fourth proportional to 517.18, 774.54 and 420.78 is: 630.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    517.18 : 774.54 = 420.78 : x
  2. Step 2: Convert to fraction form
    517.18/774.54 = 420.78/x
  3. Step 3: Cross multiply
    517.18x = 774.54 × 420.78
  4. Step 4: Simplify right side
    517.18x = 325,910.94
  5. Step 5: Solve for x
    x = 325,910.94/517.18
  6. Step 6: Final answer
    x = 630.17

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.