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Finding the Fourth Proportional to 79.40, 108.88 and 76.40

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Solution

The fourth proportional to 79.40, 108.88 and 76.40 is: 104.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.40 : 108.88 = 76.40 : x
  2. Step 2: Convert to fraction form
    79.40/108.88 = 76.40/x
  3. Step 3: Cross multiply
    79.40x = 108.88 × 76.40
  4. Step 4: Simplify right side
    79.40x = 8,318.43
  5. Step 5: Solve for x
    x = 8,318.43/79.40
  6. Step 6: Final answer
    x = 104.77

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.