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Finding the Fourth Proportional to 386.85, 580.38 and 143.45

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Solution

The fourth proportional to 386.85, 580.38 and 143.45 is: 215.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.85 : 580.38 = 143.45 : x
  2. Step 2: Convert to fraction form
    386.85/580.38 = 143.45/x
  3. Step 3: Cross multiply
    386.85x = 580.38 × 143.45
  4. Step 4: Simplify right side
    386.85x = 83,255.51
  5. Step 5: Solve for x
    x = 83,255.51/386.85
  6. Step 6: Final answer
    x = 215.21

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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.