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Finding the Fourth Proportional to 121.34, 167.31 and 99.21

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Solution

The fourth proportional to 121.34, 167.31 and 99.21 is: 136.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.34 : 167.31 = 99.21 : x
  2. Step 2: Convert to fraction form
    121.34/167.31 = 99.21/x
  3. Step 3: Cross multiply
    121.34x = 167.31 × 99.21
  4. Step 4: Simplify right side
    121.34x = 16,598.83
  5. Step 5: Solve for x
    x = 16,598.83/121.34
  6. Step 6: Final answer
    x = 136.80

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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.