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Finding the Fourth Proportional to 986.20, 1,479.30 and 813.40

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Solution

The fourth proportional to 986.20, 1,479.30 and 813.40 is: 1,220.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    986.20 : 1,479.30 = 813.40 : x
  2. Step 2: Convert to fraction form
    986.20/1,479.30 = 813.40/x
  3. Step 3: Cross multiply
    986.20x = 1,479.30 × 813.40
  4. Step 4: Simplify right side
    986.20x = 1,203,262.62
  5. Step 5: Solve for x
    x = 1,203,262.62/986.20
  6. Step 6: Final answer
    x = 1,220.10

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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.