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Finding the Fourth Proportional to 986.32, 1,478.36 and 438.80

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Solution

The fourth proportional to 986.32, 1,478.36 and 438.80 is: 657.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    986.32 : 1,478.36 = 438.80 : x
  2. Step 2: Convert to fraction form
    986.32/1,478.36 = 438.80/x
  3. Step 3: Cross multiply
    986.32x = 1,478.36 × 438.80
  4. Step 4: Simplify right side
    986.32x = 648,704.37
  5. Step 5: Solve for x
    x = 648,704.37/986.32
  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.