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Finding the Fourth Proportional to 84.28, 116.31 and 77.74

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Solution

The fourth proportional to 84.28, 116.31 and 77.74 is: 107.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.28 : 116.31 = 77.74 : x
  2. Step 2: Convert to fraction form
    84.28/116.31 = 77.74/x
  3. Step 3: Cross multiply
    84.28x = 116.31 × 77.74
  4. Step 4: Simplify right side
    84.28x = 9,041.94
  5. Step 5: Solve for x
    x = 9,041.94/84.28
  6. Step 6: Final answer
    x = 107.28

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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.