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Finding the Fourth Proportional to 986.52, 1,478.66 and 438.20

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Solution

The fourth proportional to 986.52, 1,478.66 and 438.20 is: 656.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    986.52 : 1,478.66 = 438.20 : x
  2. Step 2: Convert to fraction form
    986.52/1,478.66 = 438.20/x
  3. Step 3: Cross multiply
    986.52x = 1,478.66 × 438.20
  4. Step 4: Simplify right side
    986.52x = 647,948.81
  5. Step 5: Solve for x
    x = 647,948.81/986.52
  6. Step 6: Final answer
    x = 656.80

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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.