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Finding the Fourth Proportional to 719.36, 1,079.22 and 390.15

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Solution

The fourth proportional to 719.36, 1,079.22 and 390.15 is: 585.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    719.36 : 1,079.22 = 390.15 : x
  2. Step 2: Convert to fraction form
    719.36/1,079.22 = 390.15/x
  3. Step 3: Cross multiply
    719.36x = 1,079.22 × 390.15
  4. Step 4: Simplify right side
    719.36x = 421,059.15
  5. Step 5: Solve for x
    x = 421,059.15/719.36
  6. Step 6: Final answer
    x = 585.33

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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.