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Finding the Fourth Proportional to 121.50, 167.71 and 74.90

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Solution

The fourth proportional to 121.50, 167.71 and 74.90 is: 103.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.50 : 167.71 = 74.90 : x
  2. Step 2: Convert to fraction form
    121.50/167.71 = 74.90/x
  3. Step 3: Cross multiply
    121.50x = 167.71 × 74.90
  4. Step 4: Simplify right side
    121.50x = 12,561.48
  5. Step 5: Solve for x
    x = 12,561.48/121.50
  6. Step 6: Final answer
    x = 103.39

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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.