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Finding the Third Proportional to 278.81 and 438.56

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Solution

The third proportional to 278.81 and 438.56 is: 689.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    278.81 : 438.56 = 438.56 : x
  2. Step 2: Convert to fraction form
    278.81/438.56 = 438.56/x
  3. Step 3: Cross multiply
    278.81x = 438.56 × 438.56
  4. Step 4: Simplify right side
    278.81x = 192,337.07
  5. Step 5: Solve for x
    x = 192,337.07/278.81
  6. Step 6: Final answer
    x = 689.84

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Why These Related Problems?

These problems maintain the same ratio (1.57) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.