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Finding the Fourth Proportional to 756.11, 1,131.74 and 390.40

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Solution

The fourth proportional to 756.11, 1,131.74 and 390.40 is: 584.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    756.11 : 1,131.74 = 390.40 : x
  2. Step 2: Convert to fraction form
    756.11/1,131.74 = 390.40/x
  3. Step 3: Cross multiply
    756.11x = 1,131.74 × 390.40
  4. Step 4: Simplify right side
    756.11x = 441,827.98
  5. Step 5: Solve for x
    x = 441,827.98/756.11
  6. Step 6: Final answer
    x = 584.34

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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.