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Finding the Fourth Proportional to 771.86, 1,158.40 and 285.05

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Solution

The fourth proportional to 771.86, 1,158.40 and 285.05 is: 427.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    771.86 : 1,158.40 = 285.05 : x
  2. Step 2: Convert to fraction form
    771.86/1,158.40 = 285.05/x
  3. Step 3: Cross multiply
    771.86x = 1,158.40 × 285.05
  4. Step 4: Simplify right side
    771.86x = 330,205.17
  5. Step 5: Solve for x
    x = 330,205.17/771.86
  6. Step 6: Final answer
    x = 427.80

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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.