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Finding the Fourth Proportional to 84.40, 126.75 and 72.31

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Solution

The fourth proportional to 84.40, 126.75 and 72.31 is: 108.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.40 : 126.75 = 72.31 : x
  2. Step 2: Convert to fraction form
    84.40/126.75 = 72.31/x
  3. Step 3: Cross multiply
    84.40x = 126.75 × 72.31
  4. Step 4: Simplify right side
    84.40x = 9,165.29
  5. Step 5: Solve for x
    x = 9,165.29/84.40
  6. Step 6: Final answer
    x = 108.59

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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.