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Finding the Fourth Proportional to 57.28, 85.88 and 21.18

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Solution

The fourth proportional to 57.28, 85.88 and 21.18 is: 31.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    57.28 : 85.88 = 21.18 : x
  2. Step 2: Convert to fraction form
    57.28/85.88 = 21.18/x
  3. Step 3: Cross multiply
    57.28x = 85.88 × 21.18
  4. Step 4: Simplify right side
    57.28x = 1,818.94
  5. Step 5: Solve for x
    x = 1,818.94/57.28
  6. Step 6: Final answer
    x = 31.76

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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.