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Finding the Fourth Proportional to 429.28, 643.97 and 155.40

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Solution

The fourth proportional to 429.28, 643.97 and 155.40 is: 233.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.28 : 643.97 = 155.40 : x
  2. Step 2: Convert to fraction form
    429.28/643.97 = 155.40/x
  3. Step 3: Cross multiply
    429.28x = 643.97 × 155.40
  4. Step 4: Simplify right side
    429.28x = 100,072.94
  5. Step 5: Solve for x
    x = 100,072.94/429.28
  6. Step 6: Final answer
    x = 233.12

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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.