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Finding the Fourth Proportional to 767.80, 1,151.70 and 281.20

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Solution

The fourth proportional to 767.80, 1,151.70 and 281.20 is: 421.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    767.80 : 1,151.70 = 281.20 : x
  2. Step 2: Convert to fraction form
    767.80/1,151.70 = 281.20/x
  3. Step 3: Cross multiply
    767.80x = 1,151.70 × 281.20
  4. Step 4: Simplify right side
    767.80x = 323,858.04
  5. Step 5: Solve for x
    x = 323,858.04/767.80
  6. Step 6: Final answer
    x = 421.80

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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.