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Finding the Fourth Proportional to 79.86, 120 and 70.76

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Solution

The fourth proportional to 79.86, 120 and 70.76 is: 106.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.86 : 120 = 70.76 : x
  2. Step 2: Convert to fraction form
    79.86/120 = 70.76/x
  3. Step 3: Cross multiply
    79.86x = 120 × 70.76
  4. Step 4: Simplify right side
    79.86x = 8,491.20
  5. Step 5: Solve for x
    x = 8,491.20/79.86
  6. Step 6: Final answer
    x = 106.33

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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.