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Finding the Fourth Proportional to 121.66, 167.61 and 99.70

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Solution

The fourth proportional to 121.66, 167.61 and 99.70 is: 137.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.66 : 167.61 = 99.70 : x
  2. Step 2: Convert to fraction form
    121.66/167.61 = 99.70/x
  3. Step 3: Cross multiply
    121.66x = 167.61 × 99.70
  4. Step 4: Simplify right side
    121.66x = 16,710.72
  5. Step 5: Solve for x
    x = 16,710.72/121.66
  6. Step 6: Final answer
    x = 137.36

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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.