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Finding the Fourth Proportional to 919.42, 1,268.38 and 640.34

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Solution

The fourth proportional to 919.42, 1,268.38 and 640.34 is: 883.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.42 : 1,268.38 = 640.34 : x
  2. Step 2: Convert to fraction form
    919.42/1,268.38 = 640.34/x
  3. Step 3: Cross multiply
    919.42x = 1,268.38 × 640.34
  4. Step 4: Simplify right side
    919.42x = 812,194.45
  5. Step 5: Solve for x
    x = 812,194.45/919.42
  6. Step 6: Final answer
    x = 883.38

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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.