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Finding the Fourth Proportional to 258.39, 386.78 and 189.72

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Solution

The fourth proportional to 258.39, 386.78 and 189.72 is: 283.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.39 : 386.78 = 189.72 : x
  2. Step 2: Convert to fraction form
    258.39/386.78 = 189.72/x
  3. Step 3: Cross multiply
    258.39x = 386.78 × 189.72
  4. Step 4: Simplify right side
    258.39x = 73,378.95
  5. Step 5: Solve for x
    x = 73,378.95/258.39
  6. Step 6: Final answer
    x = 283.99

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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.