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Finding the Fourth Proportional to 20.77, 31.15 and 12.77

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Solution

The fourth proportional to 20.77, 31.15 and 12.77 is: 19.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.77 : 31.15 = 12.77 : x
  2. Step 2: Convert to fraction form
    20.77/31.15 = 12.77/x
  3. Step 3: Cross multiply
    20.77x = 31.15 × 12.77
  4. Step 4: Simplify right side
    20.77x = 397.79
  5. Step 5: Solve for x
    x = 397.79/20.77
  6. Step 6: Final answer
    x = 19.15

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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.