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Finding the Fourth Proportional to 389.87, 538.02 and 215.21

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Solution

The fourth proportional to 389.87, 538.02 and 215.21 is: 296.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.87 : 538.02 = 215.21 : x
  2. Step 2: Convert to fraction form
    389.87/538.02 = 215.21/x
  3. Step 3: Cross multiply
    389.87x = 538.02 × 215.21
  4. Step 4: Simplify right side
    389.87x = 115,784.59
  5. Step 5: Solve for x
    x = 115,784.59/389.87
  6. Step 6: Final answer
    x = 296.99

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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.