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Finding the Fourth Proportional to 399.71, 551.67 and 386.21

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Solution

The fourth proportional to 399.71, 551.67 and 386.21 is: 533.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.71 : 551.67 = 386.21 : x
  2. Step 2: Convert to fraction form
    399.71/551.67 = 386.21/x
  3. Step 3: Cross multiply
    399.71x = 551.67 × 386.21
  4. Step 4: Simplify right side
    399.71x = 213,060.47
  5. Step 5: Solve for x
    x = 213,060.47/399.71
  6. Step 6: Final answer
    x = 533.04

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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.