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Finding the Fourth Proportional to 304.80, 421.92 and 278.88

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Solution

The fourth proportional to 304.80, 421.92 and 278.88 is: 386.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    304.80 : 421.92 = 278.88 : x
  2. Step 2: Convert to fraction form
    304.80/421.92 = 278.88/x
  3. Step 3: Cross multiply
    304.80x = 421.92 × 278.88
  4. Step 4: Simplify right side
    304.80x = 117,665.05
  5. Step 5: Solve for x
    x = 117,665.05/304.80
  6. Step 6: Final answer
    x = 386.04

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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.