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Finding the Fourth Proportional to 78.67, 108.49 and 74.12

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Solution

The fourth proportional to 78.67, 108.49 and 74.12 is: 102.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.67 : 108.49 = 74.12 : x
  2. Step 2: Convert to fraction form
    78.67/108.49 = 74.12/x
  3. Step 3: Cross multiply
    78.67x = 108.49 × 74.12
  4. Step 4: Simplify right side
    78.67x = 8,040.69
  5. Step 5: Solve for x
    x = 8,040.69/78.67
  6. Step 6: Final answer
    x = 102.21

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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.