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Finding the Fourth Proportional to 719.16, 1,078.72 and 428.67

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Solution

The fourth proportional to 719.16, 1,078.72 and 428.67 is: 642.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    719.16 : 1,078.72 = 428.67 : x
  2. Step 2: Convert to fraction form
    719.16/1,078.72 = 428.67/x
  3. Step 3: Cross multiply
    719.16x = 1,078.72 × 428.67
  4. Step 4: Simplify right side
    719.16x = 462,414.90
  5. Step 5: Solve for x
    x = 462,414.90/719.16
  6. Step 6: Final answer
    x = 642.99

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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.