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Finding the Fourth Proportional to 57.11, 85.68 and 21.07

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Solution

The fourth proportional to 57.11, 85.68 and 21.07 is: 31.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    57.11 : 85.68 = 21.07 : x
  2. Step 2: Convert to fraction form
    57.11/85.68 = 21.07/x
  3. Step 3: Cross multiply
    57.11x = 85.68 × 21.07
  4. Step 4: Simplify right side
    57.11x = 1,805.28
  5. Step 5: Solve for x
    x = 1,805.28/57.11
  6. Step 6: Final answer
    x = 31.61

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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.