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Finding the Fourth Proportional to 672.42, 1,008.47 and 639.48

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Solution

The fourth proportional to 672.42, 1,008.47 and 639.48 is: 959.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    672.42 : 1,008.47 = 639.48 : x
  2. Step 2: Convert to fraction form
    672.42/1,008.47 = 639.48/x
  3. Step 3: Cross multiply
    672.42x = 1,008.47 × 639.48
  4. Step 4: Simplify right side
    672.42x = 644,896.40
  5. Step 5: Solve for x
    x = 644,896.40/672.42
  6. Step 6: Final answer
    x = 959.07

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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.