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Finding the Fourth Proportional to 385.80, 578.09 and 212.21

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Solution

The fourth proportional to 385.80, 578.09 and 212.21 is: 317.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.80 : 578.09 = 212.21 : x
  2. Step 2: Convert to fraction form
    385.80/578.09 = 212.21/x
  3. Step 3: Cross multiply
    385.80x = 578.09 × 212.21
  4. Step 4: Simplify right side
    385.80x = 122,676.21
  5. Step 5: Solve for x
    x = 122,676.21/385.80
  6. Step 6: Final answer
    x = 317.98

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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.