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Finding the Fourth Proportional to 15.45, 21.20 and 13.91

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Solution

The fourth proportional to 15.45, 21.20 and 13.91 is: 19.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.45 : 21.20 = 13.91 : x
  2. Step 2: Convert to fraction form
    15.45/21.20 = 13.91/x
  3. Step 3: Cross multiply
    15.45x = 21.20 × 13.91
  4. Step 4: Simplify right side
    15.45x = 294.72
  5. Step 5: Solve for x
    x = 294.72/15.45
  6. Step 6: Final answer
    x = 19.08

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.