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Finding the Fourth Proportional to 789.56, 1,090.62 and 640.74

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Solution

The fourth proportional to 789.56, 1,090.62 and 640.74 is: 885.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    789.56 : 1,090.62 = 640.74 : x
  2. Step 2: Convert to fraction form
    789.56/1,090.62 = 640.74/x
  3. Step 3: Cross multiply
    789.56x = 1,090.62 × 640.74
  4. Step 4: Simplify right side
    789.56x = 698,795.20
  5. Step 5: Solve for x
    x = 698,795.20/789.56
  6. Step 6: Final answer
    x = 885.04

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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.