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Finding the Fourth Proportional to 385.30, 578 and 211.90

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Solution

The fourth proportional to 385.30, 578 and 211.90 is: 317.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.30 : 578 = 211.90 : x
  2. Step 2: Convert to fraction form
    385.30/578 = 211.90/x
  3. Step 3: Cross multiply
    385.30x = 578 × 211.90
  4. Step 4: Simplify right side
    385.30x = 122,478.20
  5. Step 5: Solve for x
    x = 122,478.20/385.30
  6. Step 6: Final answer
    x = 317.88

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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.