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Finding the Fourth Proportional to 385.50, 531.75 and 311.91

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Solution

The fourth proportional to 385.50, 531.75 and 311.91 is: 430.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.50 : 531.75 = 311.91 : x
  2. Step 2: Convert to fraction form
    385.50/531.75 = 311.91/x
  3. Step 3: Cross multiply
    385.50x = 531.75 × 311.91
  4. Step 4: Simplify right side
    385.50x = 165,858.14
  5. Step 5: Solve for x
    x = 165,858.14/385.50
  6. Step 6: Final answer
    x = 430.24

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.