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Finding the Fourth Proportional to 124.53, 186.81 and 81.21

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Solution

The fourth proportional to 124.53, 186.81 and 81.21 is: 121.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    124.53 : 186.81 = 81.21 : x
  2. Step 2: Convert to fraction form
    124.53/186.81 = 81.21/x
  3. Step 3: Cross multiply
    124.53x = 186.81 × 81.21
  4. Step 4: Simplify right side
    124.53x = 15,170.84
  5. Step 5: Solve for x
    x = 15,170.84/124.53
  6. Step 6: Final answer
    x = 121.82

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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.