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Finding the Fourth Proportional to 521.21, 719.31 and 389.99

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Solution

The fourth proportional to 521.21, 719.31 and 389.99 is: 538.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.21 : 719.31 = 389.99 : x
  2. Step 2: Convert to fraction form
    521.21/719.31 = 389.99/x
  3. Step 3: Cross multiply
    521.21x = 719.31 × 389.99
  4. Step 4: Simplify right side
    521.21x = 280,520.11
  5. Step 5: Solve for x
    x = 280,520.11/521.21
  6. Step 6: Final answer
    x = 538.21

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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.