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Finding the Fourth Proportional to 258.21, 386.87 and 189.90

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Solution

The fourth proportional to 258.21, 386.87 and 189.90 is: 284.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.21 : 386.87 = 189.90 : x
  2. Step 2: Convert to fraction form
    258.21/386.87 = 189.90/x
  3. Step 3: Cross multiply
    258.21x = 386.87 × 189.90
  4. Step 4: Simplify right side
    258.21x = 73,465.66
  5. Step 5: Solve for x
    x = 73,465.66/258.21
  6. Step 6: Final answer
    x = 284.52

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.