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Finding the Fourth Proportional to 857.72, 1,279.30 and 728.66

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Solution

The fourth proportional to 857.72, 1,279.30 and 728.66 is: 1,086.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.72 : 1,279.30 = 728.66 : x
  2. Step 2: Convert to fraction form
    857.72/1,279.30 = 728.66/x
  3. Step 3: Cross multiply
    857.72x = 1,279.30 × 728.66
  4. Step 4: Simplify right side
    857.72x = 932,174.74
  5. Step 5: Solve for x
    x = 932,174.74/857.72
  6. Step 6: Final answer
    x = 1,086.81

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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.