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Finding the Fourth Proportional to 850.40, 1,275.44 and 387.90

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Solution

The fourth proportional to 850.40, 1,275.44 and 387.90 is: 581.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    850.40 : 1,275.44 = 387.90 : x
  2. Step 2: Convert to fraction form
    850.40/1,275.44 = 387.90/x
  3. Step 3: Cross multiply
    850.40x = 1,275.44 × 387.90
  4. Step 4: Simplify right side
    850.40x = 494,743.18
  5. Step 5: Solve for x
    x = 494,743.18/850.40
  6. Step 6: Final answer
    x = 581.78

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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.