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Finding the Third Proportional to 390.09 and 556.45

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Solution

The third proportional to 390.09 and 556.45 is: 793.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.09 : 556.45 = 556.45 : x
  2. Step 2: Convert to fraction form
    390.09/556.45 = 556.45/x
  3. Step 3: Cross multiply
    390.09x = 556.45 × 556.45
  4. Step 4: Simplify right side
    390.09x = 309,640.08
  5. Step 5: Solve for x
    x = 309,640.08/390.09
  6. Step 6: Final answer
    x = 793.76

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Why These Related Problems?

These problems maintain the same ratio (1.43) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.