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Finding the Fourth Proportional to 1,078.08, 1,616.76 and 428.40

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Solution

The fourth proportional to 1,078.08, 1,616.76 and 428.40 is: 642.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,078.08 : 1,616.76 = 428.40 : x
  2. Step 2: Convert to fraction form
    1,078.08/1,616.76 = 428.40/x
  3. Step 3: Cross multiply
    1,078.08x = 1,616.76 × 428.40
  4. Step 4: Simplify right side
    1,078.08x = 692,619.98
  5. Step 5: Solve for x
    x = 692,619.98/1,078.08
  6. Step 6: Final answer
    x = 642.46

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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.