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Finding the Fourth Proportional to 79.78, 109.96 and 61.36

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Solution

The fourth proportional to 79.78, 109.96 and 61.36 is: 84.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.78 : 109.96 = 61.36 : x
  2. Step 2: Convert to fraction form
    79.78/109.96 = 61.36/x
  3. Step 3: Cross multiply
    79.78x = 109.96 × 61.36
  4. Step 4: Simplify right side
    79.78x = 6,747.15
  5. Step 5: Solve for x
    x = 6,747.15/79.78
  6. Step 6: Final answer
    x = 84.57

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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.