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Finding the Fourth Proportional to 107.20, 147.78 and 78.16

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Solution

The fourth proportional to 107.20, 147.78 and 78.16 is: 107.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    107.20 : 147.78 = 78.16 : x
  2. Step 2: Convert to fraction form
    107.20/147.78 = 78.16/x
  3. Step 3: Cross multiply
    107.20x = 147.78 × 78.16
  4. Step 4: Simplify right side
    107.20x = 11,550.48
  5. Step 5: Solve for x
    x = 11,550.48/107.20
  6. Step 6: Final answer
    x = 107.75

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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.