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Finding the Fourth Proportional to 811.30, 1,218.15 and 628.90

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Solution

The fourth proportional to 811.30, 1,218.15 and 628.90 is: 944.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.30 : 1,218.15 = 628.90 : x
  2. Step 2: Convert to fraction form
    811.30/1,218.15 = 628.90/x
  3. Step 3: Cross multiply
    811.30x = 1,218.15 × 628.90
  4. Step 4: Simplify right side
    811.30x = 766,094.54
  5. Step 5: Solve for x
    x = 766,094.54/811.30
  6. Step 6: Final answer
    x = 944.28

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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.