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Finding the Fourth Proportional to 986.26, 1,478.40 and 639.82

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Solution

The fourth proportional to 986.26, 1,478.40 and 639.82 is: 959.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    986.26 : 1,478.40 = 639.82 : x
  2. Step 2: Convert to fraction form
    986.26/1,478.40 = 639.82/x
  3. Step 3: Cross multiply
    986.26x = 1,478.40 × 639.82
  4. Step 4: Simplify right side
    986.26x = 945,909.89
  5. Step 5: Solve for x
    x = 945,909.89/986.26
  6. Step 6: Final answer
    x = 959.09

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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.