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Finding the Fourth Proportional to 79.12, 118.74 and 72.40

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Solution

The fourth proportional to 79.12, 118.74 and 72.40 is: 108.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.12 : 118.74 = 72.40 : x
  2. Step 2: Convert to fraction form
    79.12/118.74 = 72.40/x
  3. Step 3: Cross multiply
    79.12x = 118.74 × 72.40
  4. Step 4: Simplify right side
    79.12x = 8,596.78
  5. Step 5: Solve for x
    x = 8,596.78/79.12
  6. Step 6: Final answer
    x = 108.65

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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.