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Finding the Fourth Proportional to 771.82, 1,157.34 and 405.70

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Solution

The fourth proportional to 771.82, 1,157.34 and 405.70 is: 608.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    771.82 : 1,157.34 = 405.70 : x
  2. Step 2: Convert to fraction form
    771.82/1,157.34 = 405.70/x
  3. Step 3: Cross multiply
    771.82x = 1,157.34 × 405.70
  4. Step 4: Simplify right side
    771.82x = 469,532.84
  5. Step 5: Solve for x
    x = 469,532.84/771.82
  6. Step 6: Final answer
    x = 608.35

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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.