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Finding the Fourth Proportional to 77.90, 107.60 and 63.20

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Solution

The fourth proportional to 77.90, 107.60 and 63.20 is: 87.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.90 : 107.60 = 63.20 : x
  2. Step 2: Convert to fraction form
    77.90/107.60 = 63.20/x
  3. Step 3: Cross multiply
    77.90x = 107.60 × 63.20
  4. Step 4: Simplify right side
    77.90x = 6,800.75
  5. Step 5: Solve for x
    x = 6,800.75/77.90
  6. Step 6: Final answer
    x = 87.30

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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.