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Finding the Fourth Proportional to 1,288.31, 1,777.67 and 728.60

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Solution

The fourth proportional to 1,288.31, 1,777.67 and 728.60 is: 1,005.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,288.31 : 1,777.67 = 728.60 : x
  2. Step 2: Convert to fraction form
    1,288.31/1,777.67 = 728.60/x
  3. Step 3: Cross multiply
    1,288.31x = 1,777.67 × 728.60
  4. Step 4: Simplify right side
    1,288.31x = 1,295,211.16
  5. Step 5: Solve for x
    x = 1,295,211.16/1,288.31
  6. Step 6: Final answer
    x = 1,005.35

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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.