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Finding the Fourth Proportional to 764.58, 1,055.28 and 485.20

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Solution

The fourth proportional to 764.58, 1,055.28 and 485.20 is: 669.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    764.58 : 1,055.28 = 485.20 : x
  2. Step 2: Convert to fraction form
    764.58/1,055.28 = 485.20/x
  3. Step 3: Cross multiply
    764.58x = 1,055.28 × 485.20
  4. Step 4: Simplify right side
    764.58x = 512,021.86
  5. Step 5: Solve for x
    x = 512,021.86/764.58
  6. Step 6: Final answer
    x = 669.68

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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.