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Finding the Fourth Proportional to 934.40, 1,289.60 and 640

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Solution

The fourth proportional to 934.40, 1,289.60 and 640 is: 883.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    934.40 : 1,289.60 = 640 : x
  2. Step 2: Convert to fraction form
    934.40/1,289.60 = 640/x
  3. Step 3: Cross multiply
    934.40x = 1,289.60 × 640
  4. Step 4: Simplify right side
    934.40x = 825,344
  5. Step 5: Solve for x
    x = 825,344/934.40
  6. Step 6: Final answer
    x = 883.29

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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.