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Finding the Fourth Proportional to 786.96, 1,178.01 and 420.84

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Solution

The fourth proportional to 786.96, 1,178.01 and 420.84 is: 629.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    786.96 : 1,178.01 = 420.84 : x
  2. Step 2: Convert to fraction form
    786.96/1,178.01 = 420.84/x
  3. Step 3: Cross multiply
    786.96x = 1,178.01 × 420.84
  4. Step 4: Simplify right side
    786.96x = 495,753.73
  5. Step 5: Solve for x
    x = 495,753.73/786.96
  6. Step 6: Final answer
    x = 629.96

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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.