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Finding the Fourth Proportional to 811.80, 1,218.20 and 349.80

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Solution

The fourth proportional to 811.80, 1,218.20 and 349.80 is: 524.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.80 : 1,218.20 = 349.80 : x
  2. Step 2: Convert to fraction form
    811.80/1,218.20 = 349.80/x
  3. Step 3: Cross multiply
    811.80x = 1,218.20 × 349.80
  4. Step 4: Simplify right side
    811.80x = 426,126.36
  5. Step 5: Solve for x
    x = 426,126.36/811.80
  6. Step 6: Final answer
    x = 524.92

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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.