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Finding the Fourth Proportional to 386, 579 and 215

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Solution

The fourth proportional to 386, 579 and 215 is: 322.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    386 : 579 = 215 : x
  2. Step 2: Convert to fraction form
    386/579 = 215/x
  3. Step 3: Cross multiply
    386x = 579 × 215
  4. Step 4: Simplify right side
    386x = 124,485
  5. Step 5: Solve for x
    x = 124,485/386
  6. Step 6: Final answer
    x = 322.50

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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.