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Finding the Fourth Proportional to 429.48, 643.89 and 155.55

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Solution

The fourth proportional to 429.48, 643.89 and 155.55 is: 233.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.48 : 643.89 = 155.55 : x
  2. Step 2: Convert to fraction form
    429.48/643.89 = 155.55/x
  3. Step 3: Cross multiply
    429.48x = 643.89 × 155.55
  4. Step 4: Simplify right side
    429.48x = 100,157.09
  5. Step 5: Solve for x
    x = 100,157.09/429.48
  6. Step 6: Final answer
    x = 233.21

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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.