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Finding the Fourth Proportional to 258.65, 386.78 and 189.45

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Solution

The fourth proportional to 258.65, 386.78 and 189.45 is: 283.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.65 : 386.78 = 189.45 : x
  2. Step 2: Convert to fraction form
    258.65/386.78 = 189.45/x
  3. Step 3: Cross multiply
    258.65x = 386.78 × 189.45
  4. Step 4: Simplify right side
    258.65x = 73,274.52
  5. Step 5: Solve for x
    x = 73,274.52/258.65
  6. Step 6: Final answer
    x = 283.30

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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.