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Finding the Fourth Proportional to 215.13, 296.90 and 121.90

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Solution

The fourth proportional to 215.13, 296.90 and 121.90 is: 168.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.13 : 296.90 = 121.90 : x
  2. Step 2: Convert to fraction form
    215.13/296.90 = 121.90/x
  3. Step 3: Cross multiply
    215.13x = 296.90 × 121.90
  4. Step 4: Simplify right side
    215.13x = 36,190.59
  5. Step 5: Solve for x
    x = 36,190.59/215.13
  6. Step 6: Final answer
    x = 168.23

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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.