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Finding the Fourth Proportional to 280.65, 420.80 and 126.55

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Solution

The fourth proportional to 280.65, 420.80 and 126.55 is: 189.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.65 : 420.80 = 126.55 : x
  2. Step 2: Convert to fraction form
    280.65/420.80 = 126.55/x
  3. Step 3: Cross multiply
    280.65x = 420.80 × 126.55
  4. Step 4: Simplify right side
    280.65x = 53,252.24
  5. Step 5: Solve for x
    x = 53,252.24/280.65
  6. Step 6: Final answer
    x = 189.75

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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.