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Finding the Fourth Proportional to 56.82, 85.12 and 20.72

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Solution

The fourth proportional to 56.82, 85.12 and 20.72 is: 31.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    56.82 : 85.12 = 20.72 : x
  2. Step 2: Convert to fraction form
    56.82/85.12 = 20.72/x
  3. Step 3: Cross multiply
    56.82x = 85.12 × 20.72
  4. Step 4: Simplify right side
    56.82x = 1,763.69
  5. Step 5: Solve for x
    x = 1,763.69/56.82
  6. Step 6: Final answer
    x = 31.04

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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.