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Finding the Fourth Proportional to 919.59, 1,268.42 and 639.87

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Solution

The fourth proportional to 919.59, 1,268.42 and 639.87 is: 882.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.59 : 1,268.42 = 639.87 : x
  2. Step 2: Convert to fraction form
    919.59/1,268.42 = 639.87/x
  3. Step 3: Cross multiply
    919.59x = 1,268.42 × 639.87
  4. Step 4: Simplify right side
    919.59x = 811,620.71
  5. Step 5: Solve for x
    x = 811,620.71/919.59
  6. Step 6: Final answer
    x = 882.59

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.