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Finding the Fourth Proportional to 390.78, 585.72 and 185.22

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Solution

The fourth proportional to 390.78, 585.72 and 185.22 is: 277.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.78 : 585.72 = 185.22 : x
  2. Step 2: Convert to fraction form
    390.78/585.72 = 185.22/x
  3. Step 3: Cross multiply
    390.78x = 585.72 × 185.22
  4. Step 4: Simplify right side
    390.78x = 108,487.06
  5. Step 5: Solve for x
    x = 108,487.06/390.78
  6. Step 6: Final answer
    x = 277.62

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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.