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Finding the Fourth Proportional to 840.20, 1,159.79 and 620.91

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Solution

The fourth proportional to 840.20, 1,159.79 and 620.91 is: 857.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.20 : 1,159.79 = 620.91 : x
  2. Step 2: Convert to fraction form
    840.20/1,159.79 = 620.91/x
  3. Step 3: Cross multiply
    840.20x = 1,159.79 × 620.91
  4. Step 4: Simplify right side
    840.20x = 720,122.10
  5. Step 5: Solve for x
    x = 720,122.10/840.20
  6. Step 6: Final answer
    x = 857.09

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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.