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Finding the Fourth Proportional to 121, 166.98 and 100.20

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Solution

The fourth proportional to 121, 166.98 and 100.20 is: 138.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    121 : 166.98 = 100.20 : x
  2. Step 2: Convert to fraction form
    121/166.98 = 100.20/x
  3. Step 3: Cross multiply
    121x = 166.98 × 100.20
  4. Step 4: Simplify right side
    121x = 16,731.40
  5. Step 5: Solve for x
    x = 16,731.40/121
  6. Step 6: Final answer
    x = 138.28

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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.