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Finding the Third Proportional to 312.19 and 485.30

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Solution

The third proportional to 312.19 and 485.30 is: 754.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.19 : 485.30 = 485.30 : x
  2. Step 2: Convert to fraction form
    312.19/485.30 = 485.30/x
  3. Step 3: Cross multiply
    312.19x = 485.30 × 485.30
  4. Step 4: Simplify right side
    312.19x = 235,513.06
  5. Step 5: Solve for x
    x = 235,513.06/312.19
  6. Step 6: Final answer
    x = 754.40

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Why These Related Problems?

These problems maintain the same ratio (1.55) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.