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Finding the Fourth Proportional to 791.78, 1,187.80 and 304.90

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Solution

The fourth proportional to 791.78, 1,187.80 and 304.90 is: 457.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    791.78 : 1,187.80 = 304.90 : x
  2. Step 2: Convert to fraction form
    791.78/1,187.80 = 304.90/x
  3. Step 3: Cross multiply
    791.78x = 1,187.80 × 304.90
  4. Step 4: Simplify right side
    791.78x = 362,156.49
  5. Step 5: Solve for x
    x = 362,156.49/791.78
  6. Step 6: Final answer
    x = 457.40

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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.