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Finding the Fourth Proportional to 771.78, 1,157.64 and 258.78

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Solution

The fourth proportional to 771.78, 1,157.64 and 258.78 is: 388.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    771.78 : 1,157.64 = 258.78 : x
  2. Step 2: Convert to fraction form
    771.78/1,157.64 = 258.78/x
  3. Step 3: Cross multiply
    771.78x = 1,157.64 × 258.78
  4. Step 4: Simplify right side
    771.78x = 299,574.08
  5. Step 5: Solve for x
    x = 299,574.08/771.78
  6. Step 6: Final answer
    x = 388.16

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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.