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Finding the Fourth Proportional to 9.99, 15.05 and 9.21

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Solution

The fourth proportional to 9.99, 15.05 and 9.21 is: 13.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    9.99 : 15.05 = 9.21 : x
  2. Step 2: Convert to fraction form
    9.99/15.05 = 9.21/x
  3. Step 3: Cross multiply
    9.99x = 15.05 × 9.21
  4. Step 4: Simplify right side
    9.99x = 138.56
  5. Step 5: Solve for x
    x = 138.56/9.99
  6. Step 6: Final answer
    x = 13.87

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.