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Finding the Fourth Proportional to 380.78, 571.15 and 120.79

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Solution

The fourth proportional to 380.78, 571.15 and 120.79 is: 181.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    380.78 : 571.15 = 120.79 : x
  2. Step 2: Convert to fraction form
    380.78/571.15 = 120.79/x
  3. Step 3: Cross multiply
    380.78x = 571.15 × 120.79
  4. Step 4: Simplify right side
    380.78x = 68,989.21
  5. Step 5: Solve for x
    x = 68,989.21/380.78
  6. Step 6: Final answer
    x = 181.18

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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.