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Finding the Fourth Proportional to 305.16, 420.90 and 206.92

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Solution

The fourth proportional to 305.16, 420.90 and 206.92 is: 285.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.16 : 420.90 = 206.92 : x
  2. Step 2: Convert to fraction form
    305.16/420.90 = 206.92/x
  3. Step 3: Cross multiply
    305.16x = 420.90 × 206.92
  4. Step 4: Simplify right side
    305.16x = 87,092.63
  5. Step 5: Solve for x
    x = 87,092.63/305.16
  6. Step 6: Final answer
    x = 285.40

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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.