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Finding the Fourth Proportional to 385.85, 531.90 and 307.20

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Solution

The fourth proportional to 385.85, 531.90 and 307.20 is: 423.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.85 : 531.90 = 307.20 : x
  2. Step 2: Convert to fraction form
    385.85/531.90 = 307.20/x
  3. Step 3: Cross multiply
    385.85x = 531.90 × 307.20
  4. Step 4: Simplify right side
    385.85x = 163,399.68
  5. Step 5: Solve for x
    x = 163,399.68/385.85
  6. Step 6: Final answer
    x = 423.49

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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.