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Finding the Fourth Proportional to 305.08, 420.69 and 280.42

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Solution

The fourth proportional to 305.08, 420.69 and 280.42 is: 386.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.08 : 420.69 = 280.42 : x
  2. Step 2: Convert to fraction form
    305.08/420.69 = 280.42/x
  3. Step 3: Cross multiply
    305.08x = 420.69 × 280.42
  4. Step 4: Simplify right side
    305.08x = 117,969.89
  5. Step 5: Solve for x
    x = 117,969.89/305.08
  6. Step 6: Final answer
    x = 386.69

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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.