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Finding the Fourth Proportional to 81.74, 123.21 and 77.34

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Solution

The fourth proportional to 81.74, 123.21 and 77.34 is: 116.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.74 : 123.21 = 77.34 : x
  2. Step 2: Convert to fraction form
    81.74/123.21 = 77.34/x
  3. Step 3: Cross multiply
    81.74x = 123.21 × 77.34
  4. Step 4: Simplify right side
    81.74x = 9,528.67
  5. Step 5: Solve for x
    x = 9,528.67/81.74
  6. Step 6: Final answer
    x = 116.57

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.