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Finding the Fourth Proportional to 980.80, 1,471.20 and 432.40

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Solution

The fourth proportional to 980.80, 1,471.20 and 432.40 is: 648.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    980.80 : 1,471.20 = 432.40 : x
  2. Step 2: Convert to fraction form
    980.80/1,471.20 = 432.40/x
  3. Step 3: Cross multiply
    980.80x = 1,471.20 × 432.40
  4. Step 4: Simplify right side
    980.80x = 636,146.88
  5. Step 5: Solve for x
    x = 636,146.88/980.80
  6. Step 6: Final answer
    x = 648.60

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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.