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Finding the Fourth Proportional to 121.80, 165.76 and 121.80

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Solution

The fourth proportional to 121.80, 165.76 and 121.80 is: 165.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.80 : 165.76 = 121.80 : x
  2. Step 2: Convert to fraction form
    121.80/165.76 = 121.80/x
  3. Step 3: Cross multiply
    121.80x = 165.76 × 121.80
  4. Step 4: Simplify right side
    121.80x = 20,189.57
  5. Step 5: Solve for x
    x = 20,189.57/121.80
  6. Step 6: Final answer
    x = 165.76

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Why These Related Problems?

These problems maintain the same ratio (1.36) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.