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Finding the Fourth Proportional to 872.40, 1,309.26 and 385.76

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Solution

The fourth proportional to 872.40, 1,309.26 and 385.76 is: 578.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    872.40 : 1,309.26 = 385.76 : x
  2. Step 2: Convert to fraction form
    872.40/1,309.26 = 385.76/x
  3. Step 3: Cross multiply
    872.40x = 1,309.26 × 385.76
  4. Step 4: Simplify right side
    872.40x = 505,060.14
  5. Step 5: Solve for x
    x = 505,060.14/872.40
  6. Step 6: Final answer
    x = 578.93

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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.