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Finding the Fourth Proportional to 20.77, 28.66 and 15.31

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Solution

The fourth proportional to 20.77, 28.66 and 15.31 is: 21.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.77 : 28.66 = 15.31 : x
  2. Step 2: Convert to fraction form
    20.77/28.66 = 15.31/x
  3. Step 3: Cross multiply
    20.77x = 28.66 × 15.31
  4. Step 4: Simplify right side
    20.77x = 438.71
  5. Step 5: Solve for x
    x = 438.71/20.77
  6. Step 6: Final answer
    x = 21.12

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.