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Finding the Fourth Proportional to 288.40, 398.34 and 218.80

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Solution

The fourth proportional to 288.40, 398.34 and 218.80 is: 302.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    288.40 : 398.34 = 218.80 : x
  2. Step 2: Convert to fraction form
    288.40/398.34 = 218.80/x
  3. Step 3: Cross multiply
    288.40x = 398.34 × 218.80
  4. Step 4: Simplify right side
    288.40x = 87,156.79
  5. Step 5: Solve for x
    x = 87,156.79/288.40
  6. Step 6: Final answer
    x = 302.21

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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.