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Finding the Fourth Proportional to 378.21, 521.91 and 212.43

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Solution

The fourth proportional to 378.21, 521.91 and 212.43 is: 293.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    378.21 : 521.91 = 212.43 : x
  2. Step 2: Convert to fraction form
    378.21/521.91 = 212.43/x
  3. Step 3: Cross multiply
    378.21x = 521.91 × 212.43
  4. Step 4: Simplify right side
    378.21x = 110,869.34
  5. Step 5: Solve for x
    x = 110,869.34/378.21
  6. Step 6: Final answer
    x = 293.14

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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.