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Finding the Fourth Proportional to 803.61, 1,205.21 and 255.65

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Solution

The fourth proportional to 803.61, 1,205.21 and 255.65 is: 383.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    803.61 : 1,205.21 = 255.65 : x
  2. Step 2: Convert to fraction form
    803.61/1,205.21 = 255.65/x
  3. Step 3: Cross multiply
    803.61x = 1,205.21 × 255.65
  4. Step 4: Simplify right side
    803.61x = 308,106.55
  5. Step 5: Solve for x
    x = 308,106.55/803.61
  6. Step 6: Final answer
    x = 383.40

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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.