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Finding the Fourth Proportional to 429.15, 642.85 and 289.90

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Solution

The fourth proportional to 429.15, 642.85 and 289.90 is: 434.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.15 : 642.85 = 289.90 : x
  2. Step 2: Convert to fraction form
    429.15/642.85 = 289.90/x
  3. Step 3: Cross multiply
    429.15x = 642.85 × 289.90
  4. Step 4: Simplify right side
    429.15x = 186,362.22
  5. Step 5: Solve for x
    x = 186,362.22/429.15
  6. Step 6: Final answer
    x = 434.26

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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.