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Finding the Fourth Proportional to 280.80, 421.29 and 189.72

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Solution

The fourth proportional to 280.80, 421.29 and 189.72 is: 284.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.80 : 421.29 = 189.72 : x
  2. Step 2: Convert to fraction form
    280.80/421.29 = 189.72/x
  3. Step 3: Cross multiply
    280.80x = 421.29 × 189.72
  4. Step 4: Simplify right side
    280.80x = 79,927.14
  5. Step 5: Solve for x
    x = 79,927.14/280.80
  6. Step 6: Final answer
    x = 284.64

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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.