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Finding the Fourth Proportional to 918.23, 1,265.67 and 638.78

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Solution

The fourth proportional to 918.23, 1,265.67 and 638.78 is: 880.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.23 : 1,265.67 = 638.78 : x
  2. Step 2: Convert to fraction form
    918.23/1,265.67 = 638.78/x
  3. Step 3: Cross multiply
    918.23x = 1,265.67 × 638.78
  4. Step 4: Simplify right side
    918.23x = 808,478.35
  5. Step 5: Solve for x
    x = 808,478.35/918.23
  6. Step 6: Final answer
    x = 880.48

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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.