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Finding the Fourth Proportional to 304.64, 420.31 and 221.78

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Solution

The fourth proportional to 304.64, 420.31 and 221.78 is: 305.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    304.64 : 420.31 = 221.78 : x
  2. Step 2: Convert to fraction form
    304.64/420.31 = 221.78/x
  3. Step 3: Cross multiply
    304.64x = 420.31 × 221.78
  4. Step 4: Simplify right side
    304.64x = 93,215.35
  5. Step 5: Solve for x
    x = 93,215.35/304.64
  6. Step 6: Final answer
    x = 305.98

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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.