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Finding the Fourth Proportional to 390.10, 538.31 and 215.44

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Solution

The fourth proportional to 390.10, 538.31 and 215.44 is: 297.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.10 : 538.31 = 215.44 : x
  2. Step 2: Convert to fraction form
    390.10/538.31 = 215.44/x
  3. Step 3: Cross multiply
    390.10x = 538.31 × 215.44
  4. Step 4: Simplify right side
    390.10x = 115,973.51
  5. Step 5: Solve for x
    x = 115,973.51/390.10
  6. Step 6: Final answer
    x = 297.29

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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.