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Finding the Fourth Proportional to 478.20, 716.49 and 420.69

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Solution

The fourth proportional to 478.20, 716.49 and 420.69 is: 630.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    478.20 : 716.49 = 420.69 : x
  2. Step 2: Convert to fraction form
    478.20/716.49 = 420.69/x
  3. Step 3: Cross multiply
    478.20x = 716.49 × 420.69
  4. Step 4: Simplify right side
    478.20x = 301,420.18
  5. Step 5: Solve for x
    x = 301,420.18/478.20
  6. Step 6: Final answer
    x = 630.32

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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.