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Finding the Fourth Proportional to 79.89, 120.51 and 76.70

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Solution

The fourth proportional to 79.89, 120.51 and 76.70 is: 115.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.89 : 120.51 = 76.70 : x
  2. Step 2: Convert to fraction form
    79.89/120.51 = 76.70/x
  3. Step 3: Cross multiply
    79.89x = 120.51 × 76.70
  4. Step 4: Simplify right side
    79.89x = 9,242.96
  5. Step 5: Solve for x
    x = 9,242.96/79.89
  6. Step 6: Final answer
    x = 115.70

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.