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Finding the Fourth Proportional to 781.18, 1,077.50 and 728.43

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Solution

The fourth proportional to 781.18, 1,077.50 and 728.43 is: 1,004.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.18 : 1,077.50 = 728.43 : x
  2. Step 2: Convert to fraction form
    781.18/1,077.50 = 728.43/x
  3. Step 3: Cross multiply
    781.18x = 1,077.50 × 728.43
  4. Step 4: Simplify right side
    781.18x = 784,881.11
  5. Step 5: Solve for x
    x = 784,881.11/781.18
  6. Step 6: Final answer
    x = 1,004.74

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.