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Finding the Fourth Proportional to 872.32, 1,305.12 and 639.68

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Solution

The fourth proportional to 872.32, 1,305.12 and 639.68 is: 957.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    872.32 : 1,305.12 = 639.68 : x
  2. Step 2: Convert to fraction form
    872.32/1,305.12 = 639.68/x
  3. Step 3: Cross multiply
    872.32x = 1,305.12 × 639.68
  4. Step 4: Simplify right side
    872.32x = 834,859.16
  5. Step 5: Solve for x
    x = 834,859.16/872.32
  6. Step 6: Final answer
    x = 957.06

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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.