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Finding the Fourth Proportional to 803.90, 1,205.67 and 392.78

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Solution

The fourth proportional to 803.90, 1,205.67 and 392.78 is: 589.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    803.90 : 1,205.67 = 392.78 : x
  2. Step 2: Convert to fraction form
    803.90/1,205.67 = 392.78/x
  3. Step 3: Cross multiply
    803.90x = 1,205.67 × 392.78
  4. Step 4: Simplify right side
    803.90x = 473,563.06
  5. Step 5: Solve for x
    x = 473,563.06/803.90
  6. Step 6: Final answer
    x = 589.08

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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.