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Finding the Fourth Proportional to 312.91, 431.98 and 292.21

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Solution

The fourth proportional to 312.91, 431.98 and 292.21 is: 403.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.91 : 431.98 = 292.21 : x
  2. Step 2: Convert to fraction form
    312.91/431.98 = 292.21/x
  3. Step 3: Cross multiply
    312.91x = 431.98 × 292.21
  4. Step 4: Simplify right side
    312.91x = 126,228.71
  5. Step 5: Solve for x
    x = 126,228.71/312.91
  6. Step 6: Final answer
    x = 403.40

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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.