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Finding the Fourth Proportional to 800.40, 1,198.80 and 487.20

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Solution

The fourth proportional to 800.40, 1,198.80 and 487.20 is: 729.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    800.40 : 1,198.80 = 487.20 : x
  2. Step 2: Convert to fraction form
    800.40/1,198.80 = 487.20/x
  3. Step 3: Cross multiply
    800.40x = 1,198.80 × 487.20
  4. Step 4: Simplify right side
    800.40x = 584,055.36
  5. Step 5: Solve for x
    x = 584,055.36/800.40
  6. Step 6: Final answer
    x = 729.70

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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.