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Finding the Fourth Proportional to 665.91, 918.86 and 386.12

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Solution

The fourth proportional to 665.91, 918.86 and 386.12 is: 532.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.91 : 918.86 = 386.12 : x
  2. Step 2: Convert to fraction form
    665.91/918.86 = 386.12/x
  3. Step 3: Cross multiply
    665.91x = 918.86 × 386.12
  4. Step 4: Simplify right side
    665.91x = 354,790.22
  5. Step 5: Solve for x
    x = 354,790.22/665.91
  6. Step 6: Final answer
    x = 532.79

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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.