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Finding the Fourth Proportional to 986.70, 1,479.60 and 438.60

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Solution

The fourth proportional to 986.70, 1,479.60 and 438.60 is: 657.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    986.70 : 1,479.60 = 438.60 : x
  2. Step 2: Convert to fraction form
    986.70/1,479.60 = 438.60/x
  3. Step 3: Cross multiply
    986.70x = 1,479.60 × 438.60
  4. Step 4: Simplify right side
    986.70x = 648,952.56
  5. Step 5: Solve for x
    x = 648,952.56/986.70
  6. Step 6: Final answer
    x = 657.70

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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.