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Finding the Fourth Proportional to 321.78, 444.45 and 290.69

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Solution

The fourth proportional to 321.78, 444.45 and 290.69 is: 401.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.78 : 444.45 = 290.69 : x
  2. Step 2: Convert to fraction form
    321.78/444.45 = 290.69/x
  3. Step 3: Cross multiply
    321.78x = 444.45 × 290.69
  4. Step 4: Simplify right side
    321.78x = 129,194.95
  5. Step 5: Solve for x
    x = 129,194.95/321.78
  6. Step 6: Final answer
    x = 401.50

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.