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Finding the Fourth Proportional to 389.95, 538.12 and 212.90

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Solution

The fourth proportional to 389.95, 538.12 and 212.90 is: 293.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.95 : 538.12 = 212.90 : x
  2. Step 2: Convert to fraction form
    389.95/538.12 = 212.90/x
  3. Step 3: Cross multiply
    389.95x = 538.12 × 212.90
  4. Step 4: Simplify right side
    389.95x = 114,564.68
  5. Step 5: Solve for x
    x = 114,564.68/389.95
  6. Step 6: Final answer
    x = 293.80

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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.