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Finding the Fourth Proportional to 312.40, 468.70 and 209.80

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Solution

The fourth proportional to 312.40, 468.70 and 209.80 is: 314.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.40 : 468.70 = 209.80 : x
  2. Step 2: Convert to fraction form
    312.40/468.70 = 209.80/x
  3. Step 3: Cross multiply
    312.40x = 468.70 × 209.80
  4. Step 4: Simplify right side
    312.40x = 98,333.26
  5. Step 5: Solve for x
    x = 98,333.26/312.40
  6. Step 6: Final answer
    x = 314.77

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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.