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Finding the Fourth Proportional to 309.28, 426.72 and 286

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Solution

The fourth proportional to 309.28, 426.72 and 286 is: 394.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.28 : 426.72 = 286 : x
  2. Step 2: Convert to fraction form
    309.28/426.72 = 286/x
  3. Step 3: Cross multiply
    309.28x = 426.72 × 286
  4. Step 4: Simplify right side
    309.28x = 122,041.92
  5. Step 5: Solve for x
    x = 122,041.92/309.28
  6. Step 6: Final answer
    x = 394.60

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.