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Finding the Fourth Proportional to 280.40, 420.80 and 199.36

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Solution

The fourth proportional to 280.40, 420.80 and 199.36 is: 299.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.40 : 420.80 = 199.36 : x
  2. Step 2: Convert to fraction form
    280.40/420.80 = 199.36/x
  3. Step 3: Cross multiply
    280.40x = 420.80 × 199.36
  4. Step 4: Simplify right side
    280.40x = 83,890.69
  5. Step 5: Solve for x
    x = 83,890.69/280.40
  6. Step 6: Final answer
    x = 299.18

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.