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Finding the Fourth Proportional to 81.30, 121.65 and 74.10

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Solution

The fourth proportional to 81.30, 121.65 and 74.10 is: 110.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.30 : 121.65 = 74.10 : x
  2. Step 2: Convert to fraction form
    81.30/121.65 = 74.10/x
  3. Step 3: Cross multiply
    81.30x = 121.65 × 74.10
  4. Step 4: Simplify right side
    81.30x = 9,014.27
  5. Step 5: Solve for x
    x = 9,014.27/81.30
  6. Step 6: Final answer
    x = 110.88

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.