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Finding the Fourth Proportional to 1,215, 1,823.72 and 639.09

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Solution

The fourth proportional to 1,215, 1,823.72 and 639.09 is: 959.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,215 : 1,823.72 = 639.09 : x
  2. Step 2: Convert to fraction form
    1,215/1,823.72 = 639.09/x
  3. Step 3: Cross multiply
    1,215x = 1,823.72 × 639.09
  4. Step 4: Simplify right side
    1,215x = 1,165,518.02
  5. Step 5: Solve for x
    x = 1,165,518.02/1,215
  6. Step 6: Final answer
    x = 959.27

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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.