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Finding the Fourth Proportional to 79.65, 110.66 and 78.90

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Solution

The fourth proportional to 79.65, 110.66 and 78.90 is: 109.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.65 : 110.66 = 78.90 : x
  2. Step 2: Convert to fraction form
    79.65/110.66 = 78.90/x
  3. Step 3: Cross multiply
    79.65x = 110.66 × 78.90
  4. Step 4: Simplify right side
    79.65x = 8,730.68
  5. Step 5: Solve for x
    x = 8,730.68/79.65
  6. Step 6: Final answer
    x = 109.61

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.