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Finding the Fourth Proportional to 79.76, 119.76 and 78.32

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Solution

The fourth proportional to 79.76, 119.76 and 78.32 is: 117.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.76 : 119.76 = 78.32 : x
  2. Step 2: Convert to fraction form
    79.76/119.76 = 78.32/x
  3. Step 3: Cross multiply
    79.76x = 119.76 × 78.32
  4. Step 4: Simplify right side
    79.76x = 9,379.60
  5. Step 5: Solve for x
    x = 9,379.60/79.76
  6. Step 6: Final answer
    x = 117.60

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.