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Finding the Fourth Proportional to 986.87, 1,479.27 and 431.09

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Solution

The fourth proportional to 986.87, 1,479.27 and 431.09 is: 646.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    986.87 : 1,479.27 = 431.09 : x
  2. Step 2: Convert to fraction form
    986.87/1,479.27 = 431.09/x
  3. Step 3: Cross multiply
    986.87x = 1,479.27 × 431.09
  4. Step 4: Simplify right side
    986.87x = 637,696.35
  5. Step 5: Solve for x
    x = 637,696.35/986.87
  6. Step 6: Final answer
    x = 646.18

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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.