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Finding the Fourth Proportional to 159.86, 220.43 and 100.78

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Solution

The fourth proportional to 159.86, 220.43 and 100.78 is: 138.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    159.86 : 220.43 = 100.78 : x
  2. Step 2: Convert to fraction form
    159.86/220.43 = 100.78/x
  3. Step 3: Cross multiply
    159.86x = 220.43 × 100.78
  4. Step 4: Simplify right side
    159.86x = 22,214.94
  5. Step 5: Solve for x
    x = 22,214.94/159.86
  6. Step 6: Final answer
    x = 138.96

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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.