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Finding the Fourth Proportional to 803.80, 1,205.64 and 218.78

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Solution

The fourth proportional to 803.80, 1,205.64 and 218.78 is: 328.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    803.80 : 1,205.64 = 218.78 : x
  2. Step 2: Convert to fraction form
    803.80/1,205.64 = 218.78/x
  3. Step 3: Cross multiply
    803.80x = 1,205.64 × 218.78
  4. Step 4: Simplify right side
    803.80x = 263,763.89
  5. Step 5: Solve for x
    x = 263,763.89/803.80
  6. Step 6: Final answer
    x = 328.15

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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.