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Finding the Fourth Proportional to 1,872.12, 2,808 and 639.51

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Solution

The fourth proportional to 1,872.12, 2,808 and 639.51 is: 959.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,872.12 : 2,808 = 639.51 : x
  2. Step 2: Convert to fraction form
    1,872.12/2,808 = 639.51/x
  3. Step 3: Cross multiply
    1,872.12x = 2,808 × 639.51
  4. Step 4: Simplify right side
    1,872.12x = 1,795,744.08
  5. Step 5: Solve for x
    x = 1,795,744.08/1,872.12
  6. Step 6: Final answer
    x = 959.20

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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.