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Finding the Fourth Proportional to 15.51, 21.43 and 11.89

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Solution

The fourth proportional to 15.51, 21.43 and 11.89 is: 16.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.51 : 21.43 = 11.89 : x
  2. Step 2: Convert to fraction form
    15.51/21.43 = 11.89/x
  3. Step 3: Cross multiply
    15.51x = 21.43 × 11.89
  4. Step 4: Simplify right side
    15.51x = 254.80
  5. Step 5: Solve for x
    x = 254.80/15.51
  6. Step 6: Final answer
    x = 16.43

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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.