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Finding the Fourth Proportional to 386.43, 579.28 and 215.07

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Solution

The fourth proportional to 386.43, 579.28 and 215.07 is: 322.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.43 : 579.28 = 215.07 : x
  2. Step 2: Convert to fraction form
    386.43/579.28 = 215.07/x
  3. Step 3: Cross multiply
    386.43x = 579.28 × 215.07
  4. Step 4: Simplify right side
    386.43x = 124,585.75
  5. Step 5: Solve for x
    x = 124,585.75/386.43
  6. Step 6: Final answer
    x = 322.40

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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.