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Finding the Third Proportional to 218.81 and 320.91

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Solution

The third proportional to 218.81 and 320.91 is: 470.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    218.81 : 320.91 = 320.91 : x
  2. Step 2: Convert to fraction form
    218.81/320.91 = 320.91/x
  3. Step 3: Cross multiply
    218.81x = 320.91 × 320.91
  4. Step 4: Simplify right side
    218.81x = 102,980.82
  5. Step 5: Solve for x
    x = 102,980.82/218.81
  6. Step 6: Final answer
    x = 470.64

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Why These Related Problems?

These problems maintain the same ratio (1.47) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.