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Finding the Fourth Proportional to 213.18, 319.20 and 121.75

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Solution

The fourth proportional to 213.18, 319.20 and 121.75 is: 182.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.18 : 319.20 = 121.75 : x
  2. Step 2: Convert to fraction form
    213.18/319.20 = 121.75/x
  3. Step 3: Cross multiply
    213.18x = 319.20 × 121.75
  4. Step 4: Simplify right side
    213.18x = 38,861.19
  5. Step 5: Solve for x
    x = 38,861.19/213.18
  6. Step 6: Final answer
    x = 182.30

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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.