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Finding the Fourth Proportional to 76.81, 106.09 and 52.21

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Solution

The fourth proportional to 76.81, 106.09 and 52.21 is: 72.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.81 : 106.09 = 52.21 : x
  2. Step 2: Convert to fraction form
    76.81/106.09 = 52.21/x
  3. Step 3: Cross multiply
    76.81x = 106.09 × 52.21
  4. Step 4: Simplify right side
    76.81x = 5,539.09
  5. Step 5: Solve for x
    x = 5,539.09/76.81
  6. Step 6: Final answer
    x = 72.11

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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.