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Finding the Fourth Proportional to 1,078.02, 1,617.05 and 428.70

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Solution

The fourth proportional to 1,078.02, 1,617.05 and 428.70 is: 643.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,078.02 : 1,617.05 = 428.70 : x
  2. Step 2: Convert to fraction form
    1,078.02/1,617.05 = 428.70/x
  3. Step 3: Cross multiply
    1,078.02x = 1,617.05 × 428.70
  4. Step 4: Simplify right side
    1,078.02x = 693,229.34
  5. Step 5: Solve for x
    x = 693,229.34/1,078.02
  6. Step 6: Final answer
    x = 643.06

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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.