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Finding the Fourth Proportional to 9.90, 13.65 and 7.31

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Solution

The fourth proportional to 9.90, 13.65 and 7.31 is: 10.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    9.90 : 13.65 = 7.31 : x
  2. Step 2: Convert to fraction form
    9.90/13.65 = 7.31/x
  3. Step 3: Cross multiply
    9.90x = 13.65 × 7.31
  4. Step 4: Simplify right side
    9.90x = 99.78
  5. Step 5: Solve for x
    x = 99.78/9.90
  6. Step 6: Final answer
    x = 10.08

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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.