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Finding the Fourth Proportional to 980.96, 1,471.40 and 287.60

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Solution

The fourth proportional to 980.96, 1,471.40 and 287.60 is: 431.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    980.96 : 1,471.40 = 287.60 : x
  2. Step 2: Convert to fraction form
    980.96/1,471.40 = 287.60/x
  3. Step 3: Cross multiply
    980.96x = 1,471.40 × 287.60
  4. Step 4: Simplify right side
    980.96x = 423,173.20
  5. Step 5: Solve for x
    x = 423,173.20/980.96
  6. Step 6: Final answer
    x = 431.39

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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.