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Finding the Fourth Proportional to 871.61, 1,203.31 and 685.72

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Solution

The fourth proportional to 871.61, 1,203.31 and 685.72 is: 946.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    871.61 : 1,203.31 = 685.72 : x
  2. Step 2: Convert to fraction form
    871.61/1,203.31 = 685.72/x
  3. Step 3: Cross multiply
    871.61x = 1,203.31 × 685.72
  4. Step 4: Simplify right side
    871.61x = 825,125.47
  5. Step 5: Solve for x
    x = 825,125.47/871.61
  6. Step 6: Final answer
    x = 946.67

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.