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Finding the Fourth Proportional to 840.36, 1,157.82 and 640.82

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Solution

The fourth proportional to 840.36, 1,157.82 and 640.82 is: 882.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.36 : 1,157.82 = 640.82 : x
  2. Step 2: Convert to fraction form
    840.36/1,157.82 = 640.82/x
  3. Step 3: Cross multiply
    840.36x = 1,157.82 × 640.82
  4. Step 4: Simplify right side
    840.36x = 741,954.21
  5. Step 5: Solve for x
    x = 741,954.21/840.36
  6. Step 6: Final answer
    x = 882.90

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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.