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Finding the Fourth Proportional to 689.40, 1,033.79 and 485.28

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Solution

The fourth proportional to 689.40, 1,033.79 and 485.28 is: 727.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    689.40 : 1,033.79 = 485.28 : x
  2. Step 2: Convert to fraction form
    689.40/1,033.79 = 485.28/x
  3. Step 3: Cross multiply
    689.40x = 1,033.79 × 485.28
  4. Step 4: Simplify right side
    689.40x = 501,675.18
  5. Step 5: Solve for x
    x = 501,675.18/689.40
  6. Step 6: Final answer
    x = 727.70

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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.