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Finding the Fourth Proportional to 665.42, 918.29 and 385.65

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Solution

The fourth proportional to 665.42, 918.29 and 385.65 is: 532.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.42 : 918.29 = 385.65 : x
  2. Step 2: Convert to fraction form
    665.42/918.29 = 385.65/x
  3. Step 3: Cross multiply
    665.42x = 918.29 × 385.65
  4. Step 4: Simplify right side
    665.42x = 354,139.50
  5. Step 5: Solve for x
    x = 354,139.50/665.42
  6. Step 6: Final answer
    x = 532.21

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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.