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Finding the Fourth Proportional to 79.78, 120.30 and 74.02

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Solution

The fourth proportional to 79.78, 120.30 and 74.02 is: 111.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.78 : 120.30 = 74.02 : x
  2. Step 2: Convert to fraction form
    79.78/120.30 = 74.02/x
  3. Step 3: Cross multiply
    79.78x = 120.30 × 74.02
  4. Step 4: Simplify right side
    79.78x = 8,904.24
  5. Step 5: Solve for x
    x = 8,904.24/79.78
  6. Step 6: Final answer
    x = 111.61

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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.