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Finding the Fourth Proportional to 121.80, 158.70 and 121.80

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Solution

The fourth proportional to 121.80, 158.70 and 121.80 is: 158.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.80 : 158.70 = 121.80 : x
  2. Step 2: Convert to fraction form
    121.80/158.70 = 121.80/x
  3. Step 3: Cross multiply
    121.80x = 158.70 × 121.80
  4. Step 4: Simplify right side
    121.80x = 19,329.66
  5. Step 5: Solve for x
    x = 19,329.66/121.80
  6. Step 6: Final answer
    x = 158.70

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Why These Related Problems?

These problems maintain the same ratio (1.30) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.