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Finding the Fourth Proportional to 789.60, 1,090.80 and 617.20

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Solution

The fourth proportional to 789.60, 1,090.80 and 617.20 is: 852.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    789.60 : 1,090.80 = 617.20 : x
  2. Step 2: Convert to fraction form
    789.60/1,090.80 = 617.20/x
  3. Step 3: Cross multiply
    789.60x = 1,090.80 × 617.20
  4. Step 4: Simplify right side
    789.60x = 673,241.76
  5. Step 5: Solve for x
    x = 673,241.76/789.60
  6. Step 6: Final answer
    x = 852.64

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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.