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Finding the Fourth Proportional to 386.38, 579.78 and 155.40

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Solution

The fourth proportional to 386.38, 579.78 and 155.40 is: 233.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.38 : 579.78 = 155.40 : x
  2. Step 2: Convert to fraction form
    386.38/579.78 = 155.40/x
  3. Step 3: Cross multiply
    386.38x = 579.78 × 155.40
  4. Step 4: Simplify right side
    386.38x = 90,097.81
  5. Step 5: Solve for x
    x = 90,097.81/386.38
  6. Step 6: Final answer
    x = 233.18

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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.