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Finding the Fourth Proportional to 800.39, 1,200.65 and 280.19

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Solution

The fourth proportional to 800.39, 1,200.65 and 280.19 is: 420.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    800.39 : 1,200.65 = 280.19 : x
  2. Step 2: Convert to fraction form
    800.39/1,200.65 = 280.19/x
  3. Step 3: Cross multiply
    800.39x = 1,200.65 × 280.19
  4. Step 4: Simplify right side
    800.39x = 336,411.72
  5. Step 5: Solve for x
    x = 336,411.72/800.39
  6. Step 6: Final answer
    x = 420.31

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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.