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Finding the Fourth Proportional to 801.05, 1,201.80 and 390.20

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Solution

The fourth proportional to 801.05, 1,201.80 and 390.20 is: 585.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    801.05 : 1,201.80 = 390.20 : x
  2. Step 2: Convert to fraction form
    801.05/1,201.80 = 390.20/x
  3. Step 3: Cross multiply
    801.05x = 1,201.80 × 390.20
  4. Step 4: Simplify right side
    801.05x = 468,942.36
  5. Step 5: Solve for x
    x = 468,942.36/801.05
  6. Step 6: Final answer
    x = 585.41

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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.