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Finding the Fourth Proportional to 928.53, 1,390.73 and 721.49

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Solution

The fourth proportional to 928.53, 1,390.73 and 721.49 is: 1,080.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    928.53 : 1,390.73 = 721.49 : x
  2. Step 2: Convert to fraction form
    928.53/1,390.73 = 721.49/x
  3. Step 3: Cross multiply
    928.53x = 1,390.73 × 721.49
  4. Step 4: Simplify right side
    928.53x = 1,003,387.23
  5. Step 5: Solve for x
    x = 1,003,387.23/928.53
  6. Step 6: Final answer
    x = 1,080.62

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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.