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Finding the Fourth Proportional to 287.45, 396.80 and 221.03

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Solution

The fourth proportional to 287.45, 396.80 and 221.03 is: 305.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.45 : 396.80 = 221.03 : x
  2. Step 2: Convert to fraction form
    287.45/396.80 = 221.03/x
  3. Step 3: Cross multiply
    287.45x = 396.80 × 221.03
  4. Step 4: Simplify right side
    287.45x = 87,703.93
  5. Step 5: Solve for x
    x = 87,703.93/287.45
  6. Step 6: Final answer
    x = 305.11

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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.