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Finding the Fourth Proportional to 79.79, 120.15 and 74.39

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Solution

The fourth proportional to 79.79, 120.15 and 74.39 is: 112.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.79 : 120.15 = 74.39 : x
  2. Step 2: Convert to fraction form
    79.79/120.15 = 74.39/x
  3. Step 3: Cross multiply
    79.79x = 120.15 × 74.39
  4. Step 4: Simplify right side
    79.79x = 8,937.36
  5. Step 5: Solve for x
    x = 8,937.36/79.79
  6. Step 6: Final answer
    x = 112.02

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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.