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Finding the Fourth Proportional to 771.40, 1,157.10 and 386.56

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Solution

The fourth proportional to 771.40, 1,157.10 and 386.56 is: 579.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    771.40 : 1,157.10 = 386.56 : x
  2. Step 2: Convert to fraction form
    771.40/1,157.10 = 386.56/x
  3. Step 3: Cross multiply
    771.40x = 1,157.10 × 386.56
  4. Step 4: Simplify right side
    771.40x = 447,288.58
  5. Step 5: Solve for x
    x = 447,288.58/771.40
  6. Step 6: Final answer
    x = 579.84

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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.