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Finding the Fourth Proportional to 312.50, 431.45 and 279.70

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Solution

The fourth proportional to 312.50, 431.45 and 279.70 is: 386.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.50 : 431.45 = 279.70 : x
  2. Step 2: Convert to fraction form
    312.50/431.45 = 279.70/x
  3. Step 3: Cross multiply
    312.50x = 431.45 × 279.70
  4. Step 4: Simplify right side
    312.50x = 120,674.41
  5. Step 5: Solve for x
    x = 120,674.41/312.50
  6. Step 6: Final answer
    x = 386.16

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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.