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Finding the Fourth Proportional to 121.20, 167.28 and 76.98

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Solution

The fourth proportional to 121.20, 167.28 and 76.98 is: 106.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.20 : 167.28 = 76.98 : x
  2. Step 2: Convert to fraction form
    121.20/167.28 = 76.98/x
  3. Step 3: Cross multiply
    121.20x = 167.28 × 76.98
  4. Step 4: Simplify right side
    121.20x = 12,877.21
  5. Step 5: Solve for x
    x = 12,877.21/121.20
  6. Step 6: Final answer
    x = 106.25

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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.