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Finding the Fourth Proportional to 985.52, 1,479.87 and 639.70

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Solution

The fourth proportional to 985.52, 1,479.87 and 639.70 is: 960.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    985.52 : 1,479.87 = 639.70 : x
  2. Step 2: Convert to fraction form
    985.52/1,479.87 = 639.70/x
  3. Step 3: Cross multiply
    985.52x = 1,479.87 × 639.70
  4. Step 4: Simplify right side
    985.52x = 946,669.14
  5. Step 5: Solve for x
    x = 946,669.14/985.52
  6. Step 6: Final answer
    x = 960.58

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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.