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Finding the Fourth Proportional to 639.76, 957.72 and 422.80

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Solution

The fourth proportional to 639.76, 957.72 and 422.80 is: 632.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.76 : 957.72 = 422.80 : x
  2. Step 2: Convert to fraction form
    639.76/957.72 = 422.80/x
  3. Step 3: Cross multiply
    639.76x = 957.72 × 422.80
  4. Step 4: Simplify right side
    639.76x = 404,924.02
  5. Step 5: Solve for x
    x = 404,924.02/639.76
  6. Step 6: Final answer
    x = 632.93

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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.