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Finding the Fourth Proportional to 12.15, 16.78 and 10.21

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Solution

The fourth proportional to 12.15, 16.78 and 10.21 is: 14.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.15 : 16.78 = 10.21 : x
  2. Step 2: Convert to fraction form
    12.15/16.78 = 10.21/x
  3. Step 3: Cross multiply
    12.15x = 16.78 × 10.21
  4. Step 4: Simplify right side
    12.15x = 171.41
  5. Step 5: Solve for x
    x = 171.41/12.15
  6. Step 6: Final answer
    x = 14.11

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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.