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Finding the Fourth Proportional to 783.09, 1,172.75 and 391.86

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Solution

The fourth proportional to 783.09, 1,172.75 and 391.86 is: 586.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    783.09 : 1,172.75 = 391.86 : x
  2. Step 2: Convert to fraction form
    783.09/1,172.75 = 391.86/x
  3. Step 3: Cross multiply
    783.09x = 1,172.75 × 391.86
  4. Step 4: Simplify right side
    783.09x = 459,551.86
  5. Step 5: Solve for x
    x = 459,551.86/783.09
  6. Step 6: Final answer
    x = 586.84

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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.