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Finding the Fourth Proportional to 1,287.83, 1,777.49 and 728.62

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Solution

The fourth proportional to 1,287.83, 1,777.49 and 728.62 is: 1,005.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.83 : 1,777.49 = 728.62 : x
  2. Step 2: Convert to fraction form
    1,287.83/1,777.49 = 728.62/x
  3. Step 3: Cross multiply
    1,287.83x = 1,777.49 × 728.62
  4. Step 4: Simplify right side
    1,287.83x = 1,295,114.76
  5. Step 5: Solve for x
    x = 1,295,114.76/1,287.83
  6. Step 6: Final answer
    x = 1,005.66

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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.