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Finding the Fourth Proportional to 665.63, 918.56 and 389.63

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Solution

The fourth proportional to 665.63, 918.56 and 389.63 is: 537.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.63 : 918.56 = 389.63 : x
  2. Step 2: Convert to fraction form
    665.63/918.56 = 389.63/x
  3. Step 3: Cross multiply
    665.63x = 918.56 × 389.63
  4. Step 4: Simplify right side
    665.63x = 357,894.91
  5. Step 5: Solve for x
    x = 357,894.91/665.63
  6. Step 6: Final answer
    x = 537.68

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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.