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Finding the Fourth Proportional to 421.57, 632.49 and 385.39

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Solution

The fourth proportional to 421.57, 632.49 and 385.39 is: 578.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.57 : 632.49 = 385.39 : x
  2. Step 2: Convert to fraction form
    421.57/632.49 = 385.39/x
  3. Step 3: Cross multiply
    421.57x = 632.49 × 385.39
  4. Step 4: Simplify right side
    421.57x = 243,755.32
  5. Step 5: Solve for x
    x = 243,755.32/421.57
  6. Step 6: Final answer
    x = 578.21

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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.