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Finding the Fourth Proportional to 79.28, 109.15 and 74.72

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Solution

The fourth proportional to 79.28, 109.15 and 74.72 is: 102.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.28 : 109.15 = 74.72 : x
  2. Step 2: Convert to fraction form
    79.28/109.15 = 74.72/x
  3. Step 3: Cross multiply
    79.28x = 109.15 × 74.72
  4. Step 4: Simplify right side
    79.28x = 8,155.77
  5. Step 5: Solve for x
    x = 8,155.77/79.28
  6. Step 6: Final answer
    x = 102.87

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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.