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Finding the Fourth Proportional to 101.20, 151.79 and 78.43

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Solution

The fourth proportional to 101.20, 151.79 and 78.43 is: 117.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.20 : 151.79 = 78.43 : x
  2. Step 2: Convert to fraction form
    101.20/151.79 = 78.43/x
  3. Step 3: Cross multiply
    101.20x = 151.79 × 78.43
  4. Step 4: Simplify right side
    101.20x = 11,904.89
  5. Step 5: Solve for x
    x = 11,904.89/101.20
  6. Step 6: Final answer
    x = 117.64

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.