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Finding the Fourth Proportional to 872.65, 1,309.18 and 385.70

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Solution

The fourth proportional to 872.65, 1,309.18 and 385.70 is: 578.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    872.65 : 1,309.18 = 385.70 : x
  2. Step 2: Convert to fraction form
    872.65/1,309.18 = 385.70/x
  3. Step 3: Cross multiply
    872.65x = 1,309.18 × 385.70
  4. Step 4: Simplify right side
    872.65x = 504,953.03
  5. Step 5: Solve for x
    x = 504,953.03/872.65
  6. Step 6: Final answer
    x = 578.64

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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.