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Finding the Fourth Proportional to 74.90, 112.33 and 20.79

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Solution

The fourth proportional to 74.90, 112.33 and 20.79 is: 31.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    74.90 : 112.33 = 20.79 : x
  2. Step 2: Convert to fraction form
    74.90/112.33 = 20.79/x
  3. Step 3: Cross multiply
    74.90x = 112.33 × 20.79
  4. Step 4: Simplify right side
    74.90x = 2,335.37
  5. Step 5: Solve for x
    x = 2,335.37/74.90
  6. Step 6: Final answer
    x = 31.18

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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.