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Finding the Fourth Proportional to 939.69, 1,406.37 and 720.63

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Solution

The fourth proportional to 939.69, 1,406.37 and 720.63 is: 1,078.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.69 : 1,406.37 = 720.63 : x
  2. Step 2: Convert to fraction form
    939.69/1,406.37 = 720.63/x
  3. Step 3: Cross multiply
    939.69x = 1,406.37 × 720.63
  4. Step 4: Simplify right side
    939.69x = 1,013,472.41
  5. Step 5: Solve for x
    x = 1,013,472.41/939.69
  6. Step 6: Final answer
    x = 1,078.52

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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.