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Finding the Fourth Proportional to 1,408.80, 2,113.32 and 639.12

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Solution

The fourth proportional to 1,408.80, 2,113.32 and 639.12 is: 958.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,408.80 : 2,113.32 = 639.12 : x
  2. Step 2: Convert to fraction form
    1,408.80/2,113.32 = 639.12/x
  3. Step 3: Cross multiply
    1,408.80x = 2,113.32 × 639.12
  4. Step 4: Simplify right side
    1,408.80x = 1,350,665.08
  5. Step 5: Solve for x
    x = 1,350,665.08/1,408.80
  6. Step 6: Final answer
    x = 958.73

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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.