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Finding the Fourth Proportional to 155.31, 232.85 and 78.20

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Solution

The fourth proportional to 155.31, 232.85 and 78.20 is: 117.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    155.31 : 232.85 = 78.20 : x
  2. Step 2: Convert to fraction form
    155.31/232.85 = 78.20/x
  3. Step 3: Cross multiply
    155.31x = 232.85 × 78.20
  4. Step 4: Simplify right side
    155.31x = 18,207.31
  5. Step 5: Solve for x
    x = 18,207.31/155.31
  6. Step 6: Final answer
    x = 117.23

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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.