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Finding the Fourth Proportional to 84.24, 126.48 and 72.21

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Solution

The fourth proportional to 84.24, 126.48 and 72.21 is: 108.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.24 : 126.48 = 72.21 : x
  2. Step 2: Convert to fraction form
    84.24/126.48 = 72.21/x
  3. Step 3: Cross multiply
    84.24x = 126.48 × 72.21
  4. Step 4: Simplify right side
    84.24x = 9,133.12
  5. Step 5: Solve for x
    x = 9,133.12/84.24
  6. Step 6: Final answer
    x = 108.42

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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.