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Finding the Fourth Proportional to 289.94, 399.90 and 280.42

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Solution

The fourth proportional to 289.94, 399.90 and 280.42 is: 386.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    289.94 : 399.90 = 280.42 : x
  2. Step 2: Convert to fraction form
    289.94/399.90 = 280.42/x
  3. Step 3: Cross multiply
    289.94x = 399.90 × 280.42
  4. Step 4: Simplify right side
    289.94x = 112,139.96
  5. Step 5: Solve for x
    x = 112,139.96/289.94
  6. Step 6: Final answer
    x = 386.77

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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.