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Finding the Fourth Proportional to 642.79, 964.19 and 385.75

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Solution

The fourth proportional to 642.79, 964.19 and 385.75 is: 578.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.79 : 964.19 = 385.75 : x
  2. Step 2: Convert to fraction form
    642.79/964.19 = 385.75/x
  3. Step 3: Cross multiply
    642.79x = 964.19 × 385.75
  4. Step 4: Simplify right side
    642.79x = 371,936.29
  5. Step 5: Solve for x
    x = 371,936.29/642.79
  6. Step 6: Final answer
    x = 578.63

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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.