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Finding the Fourth Proportional to 755.40, 1,039.50 and 668.28

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Solution

The fourth proportional to 755.40, 1,039.50 and 668.28 is: 919.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    755.40 : 1,039.50 = 668.28 : x
  2. Step 2: Convert to fraction form
    755.40/1,039.50 = 668.28/x
  3. Step 3: Cross multiply
    755.40x = 1,039.50 × 668.28
  4. Step 4: Simplify right side
    755.40x = 694,677.06
  5. Step 5: Solve for x
    x = 694,677.06/755.40
  6. Step 6: Final answer
    x = 919.61

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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.