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Finding the Fourth Proportional to 390.13, 538.33 and 215.48

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Solution

The fourth proportional to 390.13, 538.33 and 215.48 is: 297.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.13 : 538.33 = 215.48 : x
  2. Step 2: Convert to fraction form
    390.13/538.33 = 215.48/x
  3. Step 3: Cross multiply
    390.13x = 538.33 × 215.48
  4. Step 4: Simplify right side
    390.13x = 115,999.35
  5. Step 5: Solve for x
    x = 115,999.35/390.13
  6. Step 6: Final answer
    x = 297.34

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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.