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Finding the Fourth Proportional to 79.71, 119.78 and 74.45

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Solution

The fourth proportional to 79.71, 119.78 and 74.45 is: 111.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.71 : 119.78 = 74.45 : x
  2. Step 2: Convert to fraction form
    79.71/119.78 = 74.45/x
  3. Step 3: Cross multiply
    79.71x = 119.78 × 74.45
  4. Step 4: Simplify right side
    79.71x = 8,916.65
  5. Step 5: Solve for x
    x = 8,916.65/79.71
  6. Step 6: Final answer
    x = 111.86

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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.