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Finding the Fourth Proportional to 639.74, 959.88 and 315.11

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Solution

The fourth proportional to 639.74, 959.88 and 315.11 is: 472.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.74 : 959.88 = 315.11 : x
  2. Step 2: Convert to fraction form
    639.74/959.88 = 315.11/x
  3. Step 3: Cross multiply
    639.74x = 959.88 × 315.11
  4. Step 4: Simplify right side
    639.74x = 302,467.79
  5. Step 5: Solve for x
    x = 302,467.79/639.74
  6. Step 6: Final answer
    x = 472.80

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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.