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Finding the Fourth Proportional to 719.89, 1,078.92 and 661.57

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Solution

The fourth proportional to 719.89, 1,078.92 and 661.57 is: 991.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    719.89 : 1,078.92 = 661.57 : x
  2. Step 2: Convert to fraction form
    719.89/1,078.92 = 661.57/x
  3. Step 3: Cross multiply
    719.89x = 1,078.92 × 661.57
  4. Step 4: Simplify right side
    719.89x = 713,778.41
  5. Step 5: Solve for x
    x = 713,778.41/719.89
  6. Step 6: Final answer
    x = 991.51

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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.