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Finding the Fourth Proportional to 20.95, 31.45 and 12.98

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Solution

The fourth proportional to 20.95, 31.45 and 12.98 is: 19.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.95 : 31.45 = 12.98 : x
  2. Step 2: Convert to fraction form
    20.95/31.45 = 12.98/x
  3. Step 3: Cross multiply
    20.95x = 31.45 × 12.98
  4. Step 4: Simplify right side
    20.95x = 408.22
  5. Step 5: Solve for x
    x = 408.22/20.95
  6. Step 6: Final answer
    x = 19.49

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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.