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Finding the Fourth Proportional to 20.83, 31.25 and 12.70

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Solution

The fourth proportional to 20.83, 31.25 and 12.70 is: 19.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.83 : 31.25 = 12.70 : x
  2. Step 2: Convert to fraction form
    20.83/31.25 = 12.70/x
  3. Step 3: Cross multiply
    20.83x = 31.25 × 12.70
  4. Step 4: Simplify right side
    20.83x = 396.88
  5. Step 5: Solve for x
    x = 396.88/20.83
  6. Step 6: Final answer
    x = 19.05

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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.