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Finding the Fourth Proportional to 305, 421.08 and 256.20

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Solution

The fourth proportional to 305, 421.08 and 256.20 is: 353.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    305 : 421.08 = 256.20 : x
  2. Step 2: Convert to fraction form
    305/421.08 = 256.20/x
  3. Step 3: Cross multiply
    305x = 421.08 × 256.20
  4. Step 4: Simplify right side
    305x = 107,880.70
  5. Step 5: Solve for x
    x = 107,880.70/305
  6. Step 6: Final answer
    x = 353.71

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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.