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Finding the Fourth Proportional to 74.86, 112.29 and 20.75

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Solution

The fourth proportional to 74.86, 112.29 and 20.75 is: 31.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    74.86 : 112.29 = 20.75 : x
  2. Step 2: Convert to fraction form
    74.86/112.29 = 20.75/x
  3. Step 3: Cross multiply
    74.86x = 112.29 × 20.75
  4. Step 4: Simplify right side
    74.86x = 2,330.02
  5. Step 5: Solve for x
    x = 2,330.02/74.86
  6. Step 6: Final answer
    x = 31.13

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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.