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Finding the Fourth Proportional to 639.54, 957.72 and 407.76

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Solution

The fourth proportional to 639.54, 957.72 and 407.76 is: 610.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.54 : 957.72 = 407.76 : x
  2. Step 2: Convert to fraction form
    639.54/957.72 = 407.76/x
  3. Step 3: Cross multiply
    639.54x = 957.72 × 407.76
  4. Step 4: Simplify right side
    639.54x = 390,519.91
  5. Step 5: Solve for x
    x = 390,519.91/639.54
  6. Step 6: Final answer
    x = 610.63

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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.