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Finding the Fourth Proportional to 811.30, 1,218.30 and 538.60

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Solution

The fourth proportional to 811.30, 1,218.30 and 538.60 is: 808.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.30 : 1,218.30 = 538.60 : x
  2. Step 2: Convert to fraction form
    811.30/1,218.30 = 538.60/x
  3. Step 3: Cross multiply
    811.30x = 1,218.30 × 538.60
  4. Step 4: Simplify right side
    811.30x = 656,176.38
  5. Step 5: Solve for x
    x = 656,176.38/811.30
  6. Step 6: Final answer
    x = 808.80

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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.