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Finding the Fourth Proportional to 121.39, 167.51 and 72.28

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Solution

The fourth proportional to 121.39, 167.51 and 72.28 is: 99.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.39 : 167.51 = 72.28 : x
  2. Step 2: Convert to fraction form
    121.39/167.51 = 72.28/x
  3. Step 3: Cross multiply
    121.39x = 167.51 × 72.28
  4. Step 4: Simplify right side
    121.39x = 12,107.26
  5. Step 5: Solve for x
    x = 12,107.26/121.39
  6. Step 6: Final answer
    x = 99.74

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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.