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Finding the Fourth Proportional to 428.70, 643.10 and 154.86

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Solution

The fourth proportional to 428.70, 643.10 and 154.86 is: 232.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.70 : 643.10 = 154.86 : x
  2. Step 2: Convert to fraction form
    428.70/643.10 = 154.86/x
  3. Step 3: Cross multiply
    428.70x = 643.10 × 154.86
  4. Step 4: Simplify right side
    428.70x = 99,590.47
  5. Step 5: Solve for x
    x = 99,590.47/428.70
  6. Step 6: Final answer
    x = 232.31

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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.