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Finding the Fourth Proportional to 661.18, 912.09 and 428.26

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Solution

The fourth proportional to 661.18, 912.09 and 428.26 is: 590.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.18 : 912.09 = 428.26 : x
  2. Step 2: Convert to fraction form
    661.18/912.09 = 428.26/x
  3. Step 3: Cross multiply
    661.18x = 912.09 × 428.26
  4. Step 4: Simplify right side
    661.18x = 390,611.66
  5. Step 5: Solve for x
    x = 390,611.66/661.18
  6. Step 6: Final answer
    x = 590.78

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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.