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Finding the Fourth Proportional to 687.09, 1,029.40 and 455.43

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Solution

The fourth proportional to 687.09, 1,029.40 and 455.43 is: 682.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.09 : 1,029.40 = 455.43 : x
  2. Step 2: Convert to fraction form
    687.09/1,029.40 = 455.43/x
  3. Step 3: Cross multiply
    687.09x = 1,029.40 × 455.43
  4. Step 4: Simplify right side
    687.09x = 468,817.36
  5. Step 5: Solve for x
    x = 468,817.36/687.09
  6. Step 6: Final answer
    x = 682.32

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.