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Finding the Fourth Proportional to 1,287.86, 1,777.25 and 698.40

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Solution

The fourth proportional to 1,287.86, 1,777.25 and 698.40 is: 963.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.86 : 1,777.25 = 698.40 : x
  2. Step 2: Convert to fraction form
    1,287.86/1,777.25 = 698.40/x
  3. Step 3: Cross multiply
    1,287.86x = 1,777.25 × 698.40
  4. Step 4: Simplify right side
    1,287.86x = 1,241,227.91
  5. Step 5: Solve for x
    x = 1,241,227.91/1,287.86
  6. Step 6: Final answer
    x = 963.79

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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.