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Finding the Fourth Proportional to 935.64, 1,289.97 and 640.40

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Solution

The fourth proportional to 935.64, 1,289.97 and 640.40 is: 882.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    935.64 : 1,289.97 = 640.40 : x
  2. Step 2: Convert to fraction form
    935.64/1,289.97 = 640.40/x
  3. Step 3: Cross multiply
    935.64x = 1,289.97 × 640.40
  4. Step 4: Simplify right side
    935.64x = 826,090.34
  5. Step 5: Solve for x
    x = 826,090.34/935.64
  6. Step 6: Final answer
    x = 882.91

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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.