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Finding the Fourth Proportional to 75.39, 113.06 and 21.28

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Solution

The fourth proportional to 75.39, 113.06 and 21.28 is: 31.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    75.39 : 113.06 = 21.28 : x
  2. Step 2: Convert to fraction form
    75.39/113.06 = 21.28/x
  3. Step 3: Cross multiply
    75.39x = 113.06 × 21.28
  4. Step 4: Simplify right side
    75.39x = 2,405.92
  5. Step 5: Solve for x
    x = 2,405.92/75.39
  6. Step 6: Final answer
    x = 31.91

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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.