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Finding the Fourth Proportional to 672.75, 1,011.15 and 640.35

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Solution

The fourth proportional to 672.75, 1,011.15 and 640.35 is: 962.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    672.75 : 1,011.15 = 640.35 : x
  2. Step 2: Convert to fraction form
    672.75/1,011.15 = 640.35/x
  3. Step 3: Cross multiply
    672.75x = 1,011.15 × 640.35
  4. Step 4: Simplify right side
    672.75x = 647,489.90
  5. Step 5: Solve for x
    x = 647,489.90/672.75
  6. Step 6: Final answer
    x = 962.45

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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.