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Finding the Fourth Proportional to 811.22, 1,215.07 and 434.90

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Solution

The fourth proportional to 811.22, 1,215.07 and 434.90 is: 651.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.22 : 1,215.07 = 434.90 : x
  2. Step 2: Convert to fraction form
    811.22/1,215.07 = 434.90/x
  3. Step 3: Cross multiply
    811.22x = 1,215.07 × 434.90
  4. Step 4: Simplify right side
    811.22x = 528,433.94
  5. Step 5: Solve for x
    x = 528,433.94/811.22
  6. Step 6: Final answer
    x = 651.41

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.