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Finding the Fourth Proportional to 20.98, 31.56 and 19.99

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Solution

The fourth proportional to 20.98, 31.56 and 19.99 is: 30.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.98 : 31.56 = 19.99 : x
  2. Step 2: Convert to fraction form
    20.98/31.56 = 19.99/x
  3. Step 3: Cross multiply
    20.98x = 31.56 × 19.99
  4. Step 4: Simplify right side
    20.98x = 630.88
  5. Step 5: Solve for x
    x = 630.88/20.98
  6. Step 6: Final answer
    x = 30.07

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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.