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Finding the Fourth Proportional to 79.61, 108.91 and 79.31

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Solution

The fourth proportional to 79.61, 108.91 and 79.31 is: 108.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.61 : 108.91 = 79.31 : x
  2. Step 2: Convert to fraction form
    79.61/108.91 = 79.31/x
  3. Step 3: Cross multiply
    79.61x = 108.91 × 79.31
  4. Step 4: Simplify right side
    79.61x = 8,637.65
  5. Step 5: Solve for x
    x = 8,637.65/79.61
  6. Step 6: Final answer
    x = 108.50

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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.