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Finding the Fourth Proportional to 213.03, 319.44 and 81.21

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Solution

The fourth proportional to 213.03, 319.44 and 81.21 is: 121.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.03 : 319.44 = 81.21 : x
  2. Step 2: Convert to fraction form
    213.03/319.44 = 81.21/x
  3. Step 3: Cross multiply
    213.03x = 319.44 × 81.21
  4. Step 4: Simplify right side
    213.03x = 25,941.72
  5. Step 5: Solve for x
    x = 25,941.72/213.03
  6. Step 6: Final answer
    x = 121.77

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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.