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Finding the Fourth Proportional to 107.80, 148.78 and 65.80

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Solution

The fourth proportional to 107.80, 148.78 and 65.80 is: 90.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    107.80 : 148.78 = 65.80 : x
  2. Step 2: Convert to fraction form
    107.80/148.78 = 65.80/x
  3. Step 3: Cross multiply
    107.80x = 148.78 × 65.80
  4. Step 4: Simplify right side
    107.80x = 9,789.72
  5. Step 5: Solve for x
    x = 9,789.72/107.80
  6. Step 6: Final answer
    x = 90.81

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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.