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Finding the Fourth Proportional to 20.63, 31.11 and 19.91

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Solution

The fourth proportional to 20.63, 31.11 and 19.91 is: 30.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.63 : 31.11 = 19.91 : x
  2. Step 2: Convert to fraction form
    20.63/31.11 = 19.91/x
  3. Step 3: Cross multiply
    20.63x = 31.11 × 19.91
  4. Step 4: Simplify right side
    20.63x = 619.24
  5. Step 5: Solve for x
    x = 619.24/20.63
  6. Step 6: Final answer
    x = 30.02

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.