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Finding the Fourth Proportional to 121.39, 167.61 and 90.35

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Solution

The fourth proportional to 121.39, 167.61 and 90.35 is: 124.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.39 : 167.61 = 90.35 : x
  2. Step 2: Convert to fraction form
    121.39/167.61 = 90.35/x
  3. Step 3: Cross multiply
    121.39x = 167.61 × 90.35
  4. Step 4: Simplify right side
    121.39x = 15,143.56
  5. Step 5: Solve for x
    x = 15,143.56/121.39
  6. Step 6: Final answer
    x = 124.75

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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.