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Finding the Fourth Proportional to 721.72, 1,077.38 and 612.40

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Solution

The fourth proportional to 721.72, 1,077.38 and 612.40 is: 914.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.72 : 1,077.38 = 612.40 : x
  2. Step 2: Convert to fraction form
    721.72/1,077.38 = 612.40/x
  3. Step 3: Cross multiply
    721.72x = 1,077.38 × 612.40
  4. Step 4: Simplify right side
    721.72x = 659,787.51
  5. Step 5: Solve for x
    x = 659,787.51/721.72
  6. Step 6: Final answer
    x = 914.19

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.