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Finding the Fourth Proportional to 1,255.87, 1,885.53 and 639.99

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Solution

The fourth proportional to 1,255.87, 1,885.53 and 639.99 is: 960.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,255.87 : 1,885.53 = 639.99 : x
  2. Step 2: Convert to fraction form
    1,255.87/1,885.53 = 639.99/x
  3. Step 3: Cross multiply
    1,255.87x = 1,885.53 × 639.99
  4. Step 4: Simplify right side
    1,255.87x = 1,206,720.34
  5. Step 5: Solve for x
    x = 1,206,720.34/1,255.87
  6. Step 6: Final answer
    x = 960.86

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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.