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Finding the Fourth Proportional to 80.65, 121.39 and 70.75

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Solution

The fourth proportional to 80.65, 121.39 and 70.75 is: 106.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.65 : 121.39 = 70.75 : x
  2. Step 2: Convert to fraction form
    80.65/121.39 = 70.75/x
  3. Step 3: Cross multiply
    80.65x = 121.39 × 70.75
  4. Step 4: Simplify right side
    80.65x = 8,588.34
  5. Step 5: Solve for x
    x = 8,588.34/80.65
  6. Step 6: Final answer
    x = 106.49

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.