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Finding the Fourth Proportional to 640.77, 876.66 and 638.04

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Solution

The fourth proportional to 640.77, 876.66 and 638.04 is: 872.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.77 : 876.66 = 638.04 : x
  2. Step 2: Convert to fraction form
    640.77/876.66 = 638.04/x
  3. Step 3: Cross multiply
    640.77x = 876.66 × 638.04
  4. Step 4: Simplify right side
    640.77x = 559,344.15
  5. Step 5: Solve for x
    x = 559,344.15/640.77
  6. Step 6: Final answer
    x = 872.92

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.