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Finding the Fourth Proportional to 660, 911.28 and 485.60

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Solution

The fourth proportional to 660, 911.28 and 485.60 is: 670.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    660 : 911.28 = 485.60 : x
  2. Step 2: Convert to fraction form
    660/911.28 = 485.60/x
  3. Step 3: Cross multiply
    660x = 911.28 × 485.60
  4. Step 4: Simplify right side
    660x = 442,517.57
  5. Step 5: Solve for x
    x = 442,517.57/660
  6. Step 6: Final answer
    x = 670.48

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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.