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Finding the Fourth Proportional to 753.21, 1,128.78 and 387.23

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Solution

The fourth proportional to 753.21, 1,128.78 and 387.23 is: 580.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    753.21 : 1,128.78 = 387.23 : x
  2. Step 2: Convert to fraction form
    753.21/1,128.78 = 387.23/x
  3. Step 3: Cross multiply
    753.21x = 1,128.78 × 387.23
  4. Step 4: Simplify right side
    753.21x = 437,091.84
  5. Step 5: Solve for x
    x = 437,091.84/753.21
  6. Step 6: Final answer
    x = 580.31

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.