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Finding the Fourth Proportional to 79.36, 109.60 and 72.88

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Solution

The fourth proportional to 79.36, 109.60 and 72.88 is: 100.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.36 : 109.60 = 72.88 : x
  2. Step 2: Convert to fraction form
    79.36/109.60 = 72.88/x
  3. Step 3: Cross multiply
    79.36x = 109.60 × 72.88
  4. Step 4: Simplify right side
    79.36x = 7,987.65
  5. Step 5: Solve for x
    x = 7,987.65/79.36
  6. Step 6: Final answer
    x = 100.65

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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.