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Finding the Fourth Proportional to 986.72, 1,478.28 and 662.40

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Solution

The fourth proportional to 986.72, 1,478.28 and 662.40 is: 992.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    986.72 : 1,478.28 = 662.40 : x
  2. Step 2: Convert to fraction form
    986.72/1,478.28 = 662.40/x
  3. Step 3: Cross multiply
    986.72x = 1,478.28 × 662.40
  4. Step 4: Simplify right side
    986.72x = 979,212.67
  5. Step 5: Solve for x
    x = 979,212.67/986.72
  6. Step 6: Final answer
    x = 992.39

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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.