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Finding the Fourth Proportional to 213.20, 319.90 and 91.50

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Solution

The fourth proportional to 213.20, 319.90 and 91.50 is: 137.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.20 : 319.90 = 91.50 : x
  2. Step 2: Convert to fraction form
    213.20/319.90 = 91.50/x
  3. Step 3: Cross multiply
    213.20x = 319.90 × 91.50
  4. Step 4: Simplify right side
    213.20x = 29,269.02
  5. Step 5: Solve for x
    x = 29,269.02/213.20
  6. Step 6: Final answer
    x = 137.29

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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.