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Finding the Fourth Proportional to 411.20, 615.80 and 218.40

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Solution

The fourth proportional to 411.20, 615.80 and 218.40 is: 327.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    411.20 : 615.80 = 218.40 : x
  2. Step 2: Convert to fraction form
    411.20/615.80 = 218.40/x
  3. Step 3: Cross multiply
    411.20x = 615.80 × 218.40
  4. Step 4: Simplify right side
    411.20x = 134,490.72
  5. Step 5: Solve for x
    x = 134,490.72/411.20
  6. Step 6: Final answer
    x = 327.07

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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.