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Finding the Fourth Proportional to 321.57, 442.80 and 290.70

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Solution

The fourth proportional to 321.57, 442.80 and 290.70 is: 400.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.57 : 442.80 = 290.70 : x
  2. Step 2: Convert to fraction form
    321.57/442.80 = 290.70/x
  3. Step 3: Cross multiply
    321.57x = 442.80 × 290.70
  4. Step 4: Simplify right side
    321.57x = 128,721.96
  5. Step 5: Solve for x
    x = 128,721.96/321.57
  6. Step 6: Final answer
    x = 400.29

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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.