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Finding the Fourth Proportional to 811.20, 1,213.60 and 734.40

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Solution

The fourth proportional to 811.20, 1,213.60 and 734.40 is: 1,098.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.20 : 1,213.60 = 734.40 : x
  2. Step 2: Convert to fraction form
    811.20/1,213.60 = 734.40/x
  3. Step 3: Cross multiply
    811.20x = 1,213.60 × 734.40
  4. Step 4: Simplify right side
    811.20x = 891,267.84
  5. Step 5: Solve for x
    x = 891,267.84/811.20
  6. Step 6: Final answer
    x = 1,098.70

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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.