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Finding the Fourth Proportional to 642.74, 964.76 and 399.87

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Solution

The fourth proportional to 642.74, 964.76 and 399.87 is: 600.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.74 : 964.76 = 399.87 : x
  2. Step 2: Convert to fraction form
    642.74/964.76 = 399.87/x
  3. Step 3: Cross multiply
    642.74x = 964.76 × 399.87
  4. Step 4: Simplify right side
    642.74x = 385,776.58
  5. Step 5: Solve for x
    x = 385,776.58/642.74
  6. Step 6: Final answer
    x = 600.21

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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.