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Finding the Fourth Proportional to 390.34, 538.94 and 321.22

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Solution

The fourth proportional to 390.34, 538.94 and 321.22 is: 443.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.34 : 538.94 = 321.22 : x
  2. Step 2: Convert to fraction form
    390.34/538.94 = 321.22/x
  3. Step 3: Cross multiply
    390.34x = 538.94 × 321.22
  4. Step 4: Simplify right side
    390.34x = 173,118.31
  5. Step 5: Solve for x
    x = 173,118.31/390.34
  6. Step 6: Final answer
    x = 443.51

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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.