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Finding the Fourth Proportional to 390.99, 585.81 and 217.62

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Solution

The fourth proportional to 390.99, 585.81 and 217.62 is: 326.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.99 : 585.81 = 217.62 : x
  2. Step 2: Convert to fraction form
    390.99/585.81 = 217.62/x
  3. Step 3: Cross multiply
    390.99x = 585.81 × 217.62
  4. Step 4: Simplify right side
    390.99x = 127,483.97
  5. Step 5: Solve for x
    x = 127,483.97/390.99
  6. Step 6: Final answer
    x = 326.05

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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.