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Finding the Fourth Proportional to 718.40, 991.04 and 485.52

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Solution

The fourth proportional to 718.40, 991.04 and 485.52 is: 669.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.40 : 991.04 = 485.52 : x
  2. Step 2: Convert to fraction form
    718.40/991.04 = 485.52/x
  3. Step 3: Cross multiply
    718.40x = 991.04 × 485.52
  4. Step 4: Simplify right side
    718.40x = 481,169.74
  5. Step 5: Solve for x
    x = 481,169.74/718.40
  6. Step 6: Final answer
    x = 669.78

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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.