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Finding the Fourth Proportional to 8.90, 13.31 and 8.40

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Solution

The fourth proportional to 8.90, 13.31 and 8.40 is: 12.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    8.90 : 13.31 = 8.40 : x
  2. Step 2: Convert to fraction form
    8.90/13.31 = 8.40/x
  3. Step 3: Cross multiply
    8.90x = 13.31 × 8.40
  4. Step 4: Simplify right side
    8.90x = 111.76
  5. Step 5: Solve for x
    x = 111.76/8.90
  6. Step 6: Final answer
    x = 12.56

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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.