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Finding the Fourth Proportional to 20.86, 31.16 and 18.16

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Solution

The fourth proportional to 20.86, 31.16 and 18.16 is: 27.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.86 : 31.16 = 18.16 : x
  2. Step 2: Convert to fraction form
    20.86/31.16 = 18.16/x
  3. Step 3: Cross multiply
    20.86x = 31.16 × 18.16
  4. Step 4: Simplify right side
    20.86x = 565.87
  5. Step 5: Solve for x
    x = 565.87/20.86
  6. Step 6: Final answer
    x = 27.13

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.