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Finding the Fourth Proportional to 280.65, 420.64 and 126.43

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Solution

The fourth proportional to 280.65, 420.64 and 126.43 is: 189.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.65 : 420.64 = 126.43 : x
  2. Step 2: Convert to fraction form
    280.65/420.64 = 126.43/x
  3. Step 3: Cross multiply
    280.65x = 420.64 × 126.43
  4. Step 4: Simplify right side
    280.65x = 53,180.15
  5. Step 5: Solve for x
    x = 53,180.15/280.65
  6. Step 6: Final answer
    x = 189.49

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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.