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Finding the Fourth Proportional to 699.43, 1,048.47 and 639.28

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Solution

The fourth proportional to 699.43, 1,048.47 and 639.28 is: 958.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    699.43 : 1,048.47 = 639.28 : x
  2. Step 2: Convert to fraction form
    699.43/1,048.47 = 639.28/x
  3. Step 3: Cross multiply
    699.43x = 1,048.47 × 639.28
  4. Step 4: Simplify right side
    699.43x = 670,265.90
  5. Step 5: Solve for x
    x = 670,265.90/699.43
  6. Step 6: Final answer
    x = 958.30

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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.