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Finding the Fourth Proportional to 764.75, 1,055.79 and 485.21

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Solution

The fourth proportional to 764.75, 1,055.79 and 485.21 is: 669.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    764.75 : 1,055.79 = 485.21 : x
  2. Step 2: Convert to fraction form
    764.75/1,055.79 = 485.21/x
  3. Step 3: Cross multiply
    764.75x = 1,055.79 × 485.21
  4. Step 4: Simplify right side
    764.75x = 512,274.59
  5. Step 5: Solve for x
    x = 512,274.59/764.75
  6. Step 6: Final answer
    x = 669.86

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.