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Finding the Fourth Proportional to 429.42, 642.90 and 385.68

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Solution

The fourth proportional to 429.42, 642.90 and 385.68 is: 577.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.42 : 642.90 = 385.68 : x
  2. Step 2: Convert to fraction form
    429.42/642.90 = 385.68/x
  3. Step 3: Cross multiply
    429.42x = 642.90 × 385.68
  4. Step 4: Simplify right side
    429.42x = 247,953.67
  5. Step 5: Solve for x
    x = 247,953.67/429.42
  6. Step 6: Final answer
    x = 577.42

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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.