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Finding the Fourth Proportional to 756.79, 1,128.71 and 664.85

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Solution

The fourth proportional to 756.79, 1,128.71 and 664.85 is: 991.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    756.79 : 1,128.71 = 664.85 : x
  2. Step 2: Convert to fraction form
    756.79/1,128.71 = 664.85/x
  3. Step 3: Cross multiply
    756.79x = 1,128.71 × 664.85
  4. Step 4: Simplify right side
    756.79x = 750,418.86
  5. Step 5: Solve for x
    x = 750,418.86/756.79
  6. Step 6: Final answer
    x = 991.58

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.