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Finding the Fourth Proportional to 752.15, 1,039.46 and 642.80

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Solution

The fourth proportional to 752.15, 1,039.46 and 642.80 is: 888.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    752.15 : 1,039.46 = 642.80 : x
  2. Step 2: Convert to fraction form
    752.15/1,039.46 = 642.80/x
  3. Step 3: Cross multiply
    752.15x = 1,039.46 × 642.80
  4. Step 4: Simplify right side
    752.15x = 668,164.27
  5. Step 5: Solve for x
    x = 668,164.27/752.15
  6. Step 6: Final answer
    x = 888.34

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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.