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Finding the Fourth Proportional to 79.88, 109.54 and 76.64

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Solution

The fourth proportional to 79.88, 109.54 and 76.64 is: 105.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.88 : 109.54 = 76.64 : x
  2. Step 2: Convert to fraction form
    79.88/109.54 = 76.64/x
  3. Step 3: Cross multiply
    79.88x = 109.54 × 76.64
  4. Step 4: Simplify right side
    79.88x = 8,395.15
  5. Step 5: Solve for x
    x = 8,395.15/79.88
  6. Step 6: Final answer
    x = 105.10

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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.