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Finding the Fourth Proportional to 418.40, 576.80 and 287.20

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Solution

The fourth proportional to 418.40, 576.80 and 287.20 is: 395.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    418.40 : 576.80 = 287.20 : x
  2. Step 2: Convert to fraction form
    418.40/576.80 = 287.20/x
  3. Step 3: Cross multiply
    418.40x = 576.80 × 287.20
  4. Step 4: Simplify right side
    418.40x = 165,656.96
  5. Step 5: Solve for x
    x = 165,656.96/418.40
  6. Step 6: Final answer
    x = 395.93

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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.