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Finding the Fourth Proportional to 84.32, 126.36 and 77.78

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Solution

The fourth proportional to 84.32, 126.36 and 77.78 is: 116.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.32 : 126.36 = 77.78 : x
  2. Step 2: Convert to fraction form
    84.32/126.36 = 77.78/x
  3. Step 3: Cross multiply
    84.32x = 126.36 × 77.78
  4. Step 4: Simplify right side
    84.32x = 9,828.28
  5. Step 5: Solve for x
    x = 9,828.28/84.32
  6. Step 6: Final answer
    x = 116.56

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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.