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Finding the Fourth Proportional to 771.60, 1,157.28 and 386.64

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Solution

The fourth proportional to 771.60, 1,157.28 and 386.64 is: 579.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    771.60 : 1,157.28 = 386.64 : x
  2. Step 2: Convert to fraction form
    771.60/1,157.28 = 386.64/x
  3. Step 3: Cross multiply
    771.60x = 1,157.28 × 386.64
  4. Step 4: Simplify right side
    771.60x = 447,450.74
  5. Step 5: Solve for x
    x = 447,450.74/771.60
  6. Step 6: Final answer
    x = 579.90

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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.