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Finding the Fourth Proportional to 393.61, 543.21 and 218.95

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Solution

The fourth proportional to 393.61, 543.21 and 218.95 is: 302.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    393.61 : 543.21 = 218.95 : x
  2. Step 2: Convert to fraction form
    393.61/543.21 = 218.95/x
  3. Step 3: Cross multiply
    393.61x = 543.21 × 218.95
  4. Step 4: Simplify right side
    393.61x = 118,936.71
  5. Step 5: Solve for x
    x = 118,936.71/393.61
  6. Step 6: Final answer
    x = 302.17

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.