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Finding the Fourth Proportional to 10.21, 15.31 and 5.13

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Solution

The fourth proportional to 10.21, 15.31 and 5.13 is: 7.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    10.21 : 15.31 = 5.13 : x
  2. Step 2: Convert to fraction form
    10.21/15.31 = 5.13/x
  3. Step 3: Cross multiply
    10.21x = 15.31 × 5.13
  4. Step 4: Simplify right side
    10.21x = 78.51
  5. Step 5: Solve for x
    x = 78.51/10.21
  6. Step 6: Final answer
    x = 7.69

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.