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Finding the Fourth Proportional to 107.20, 148.08 and 85.20

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Solution

The fourth proportional to 107.20, 148.08 and 85.20 is: 117.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    107.20 : 148.08 = 85.20 : x
  2. Step 2: Convert to fraction form
    107.20/148.08 = 85.20/x
  3. Step 3: Cross multiply
    107.20x = 148.08 × 85.20
  4. Step 4: Simplify right side
    107.20x = 12,616.42
  5. Step 5: Solve for x
    x = 12,616.42/107.20
  6. Step 6: Final answer
    x = 117.69

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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.