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Finding the Fourth Proportional to 665.90, 918.78 and 400.22

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Solution

The fourth proportional to 665.90, 918.78 and 400.22 is: 552.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.90 : 918.78 = 400.22 : x
  2. Step 2: Convert to fraction form
    665.90/918.78 = 400.22/x
  3. Step 3: Cross multiply
    665.90x = 918.78 × 400.22
  4. Step 4: Simplify right side
    665.90x = 367,709.54
  5. Step 5: Solve for x
    x = 367,709.54/665.90
  6. Step 6: Final answer
    x = 552.20

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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.