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Finding the Fourth Proportional to 698.70, 1,047.60 and 287.72

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Solution

The fourth proportional to 698.70, 1,047.60 and 287.72 is: 431.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    698.70 : 1,047.60 = 287.72 : x
  2. Step 2: Convert to fraction form
    698.70/1,047.60 = 287.72/x
  3. Step 3: Cross multiply
    698.70x = 1,047.60 × 287.72
  4. Step 4: Simplify right side
    698.70x = 301,415.47
  5. Step 5: Solve for x
    x = 301,415.47/698.70
  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.