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Finding the Fourth Proportional to 390.99, 586.18 and 217.51

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Solution

The fourth proportional to 390.99, 586.18 and 217.51 is: 326.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.99 : 586.18 = 217.51 : x
  2. Step 2: Convert to fraction form
    390.99/586.18 = 217.51/x
  3. Step 3: Cross multiply
    390.99x = 586.18 × 217.51
  4. Step 4: Simplify right side
    390.99x = 127,498.00
  5. Step 5: Solve for x
    x = 127,498.00/390.99
  6. Step 6: Final answer
    x = 326.09

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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.