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Finding the Fourth Proportional to 390.15, 538.31 and 222.07

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Solution

The fourth proportional to 390.15, 538.31 and 222.07 is: 306.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.15 : 538.31 = 222.07 : x
  2. Step 2: Convert to fraction form
    390.15/538.31 = 222.07/x
  3. Step 3: Cross multiply
    390.15x = 538.31 × 222.07
  4. Step 4: Simplify right side
    390.15x = 119,539.81
  5. Step 5: Solve for x
    x = 119,539.81/390.15
  6. Step 6: Final answer
    x = 306.39

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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.