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Finding the Fourth Proportional to 753.21, 1,039.42 and 421.65

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Solution

The fourth proportional to 753.21, 1,039.42 and 421.65 is: 581.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    753.21 : 1,039.42 = 421.65 : x
  2. Step 2: Convert to fraction form
    753.21/1,039.42 = 421.65/x
  3. Step 3: Cross multiply
    753.21x = 1,039.42 × 421.65
  4. Step 4: Simplify right side
    753.21x = 438,270.39
  5. Step 5: Solve for x
    x = 438,270.39/753.21
  6. Step 6: Final answer
    x = 581.87

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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.