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Finding the Fourth Proportional to 919.38, 1,268.06 and 639.63

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Solution

The fourth proportional to 919.38, 1,268.06 and 639.63 is: 882.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.38 : 1,268.06 = 639.63 : x
  2. Step 2: Convert to fraction form
    919.38/1,268.06 = 639.63/x
  3. Step 3: Cross multiply
    919.38x = 1,268.06 × 639.63
  4. Step 4: Simplify right side
    919.38x = 811,086.02
  5. Step 5: Solve for x
    x = 811,086.02/919.38
  6. Step 6: Final answer
    x = 882.21

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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.