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Finding the Fourth Proportional to 79.28, 109.35 and 78.47

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Solution

The fourth proportional to 79.28, 109.35 and 78.47 is: 108.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.28 : 109.35 = 78.47 : x
  2. Step 2: Convert to fraction form
    79.28/109.35 = 78.47/x
  3. Step 3: Cross multiply
    79.28x = 109.35 × 78.47
  4. Step 4: Simplify right side
    79.28x = 8,580.56
  5. Step 5: Solve for x
    x = 8,580.56/79.28
  6. Step 6: Final answer
    x = 108.23

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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.