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Finding the Fourth Proportional to 763.28, 1,052.12 and 639.36

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Solution

The fourth proportional to 763.28, 1,052.12 and 639.36 is: 881.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    763.28 : 1,052.12 = 639.36 : x
  2. Step 2: Convert to fraction form
    763.28/1,052.12 = 639.36/x
  3. Step 3: Cross multiply
    763.28x = 1,052.12 × 639.36
  4. Step 4: Simplify right side
    763.28x = 672,683.44
  5. Step 5: Solve for x
    x = 672,683.44/763.28
  6. Step 6: Final answer
    x = 881.31

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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.