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Finding the Fourth Proportional to 721.23, 1,079.98 and 661.08

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Solution

The fourth proportional to 721.23, 1,079.98 and 661.08 is: 989.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.23 : 1,079.98 = 661.08 : x
  2. Step 2: Convert to fraction form
    721.23/1,079.98 = 661.08/x
  3. Step 3: Cross multiply
    721.23x = 1,079.98 × 661.08
  4. Step 4: Simplify right side
    721.23x = 713,953.18
  5. Step 5: Solve for x
    x = 713,953.18/721.23
  6. Step 6: Final answer
    x = 989.91

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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.