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Finding the Fourth Proportional to 763.28, 1,053.41 and 638.72

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Solution

The fourth proportional to 763.28, 1,053.41 and 638.72 is: 881.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    763.28 : 1,053.41 = 638.72 : x
  2. Step 2: Convert to fraction form
    763.28/1,053.41 = 638.72/x
  3. Step 3: Cross multiply
    763.28x = 1,053.41 × 638.72
  4. Step 4: Simplify right side
    763.28x = 672,825.57
  5. Step 5: Solve for x
    x = 672,825.57/763.28
  6. Step 6: Final answer
    x = 881.50

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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.