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Finding the Fourth Proportional to 387.21, 534.34 and 221.45

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Solution

The fourth proportional to 387.21, 534.34 and 221.45 is: 305.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.21 : 534.34 = 221.45 : x
  2. Step 2: Convert to fraction form
    387.21/534.34 = 221.45/x
  3. Step 3: Cross multiply
    387.21x = 534.34 × 221.45
  4. Step 4: Simplify right side
    387.21x = 118,327.79
  5. Step 5: Solve for x
    x = 118,327.79/387.21
  6. Step 6: Final answer
    x = 305.59

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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.