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Finding the Fourth Proportional to 754.56, 1,040.40 and 643.68

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Solution

The fourth proportional to 754.56, 1,040.40 and 643.68 is: 887.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    754.56 : 1,040.40 = 643.68 : x
  2. Step 2: Convert to fraction form
    754.56/1,040.40 = 643.68/x
  3. Step 3: Cross multiply
    754.56x = 1,040.40 × 643.68
  4. Step 4: Simplify right side
    754.56x = 669,684.67
  5. Step 5: Solve for x
    x = 669,684.67/754.56
  6. Step 6: Final answer
    x = 887.52

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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.