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Finding the Fourth Proportional to 712.96, 1,069.20 and 280

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Solution

The fourth proportional to 712.96, 1,069.20 and 280 is: 419.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    712.96 : 1,069.20 = 280 : x
  2. Step 2: Convert to fraction form
    712.96/1,069.20 = 280/x
  3. Step 3: Cross multiply
    712.96x = 1,069.20 × 280
  4. Step 4: Simplify right side
    712.96x = 299,376
  5. Step 5: Solve for x
    x = 299,376/712.96
  6. Step 6: Final answer
    x = 419.91

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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.