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Finding the Fourth Proportional to 84.31, 126.49 and 30.21

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Solution

The fourth proportional to 84.31, 126.49 and 30.21 is: 45.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.31 : 126.49 = 30.21 : x
  2. Step 2: Convert to fraction form
    84.31/126.49 = 30.21/x
  3. Step 3: Cross multiply
    84.31x = 126.49 × 30.21
  4. Step 4: Simplify right side
    84.31x = 3,821.26
  5. Step 5: Solve for x
    x = 3,821.26/84.31
  6. Step 6: Final answer
    x = 45.32

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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.