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Finding the Fourth Proportional to 390.11, 538.34 and 215.46

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Solution

The fourth proportional to 390.11, 538.34 and 215.46 is: 297.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.11 : 538.34 = 215.46 : x
  2. Step 2: Convert to fraction form
    390.11/538.34 = 215.46/x
  3. Step 3: Cross multiply
    390.11x = 538.34 × 215.46
  4. Step 4: Simplify right side
    390.11x = 115,988.04
  5. Step 5: Solve for x
    x = 115,988.04/390.11
  6. Step 6: Final answer
    x = 297.32

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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.