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Finding the Fourth Proportional to 1,678.82, 2,519.35 and 639.78

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Solution

The fourth proportional to 1,678.82, 2,519.35 and 639.78 is: 960.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,678.82 : 2,519.35 = 639.78 : x
  2. Step 2: Convert to fraction form
    1,678.82/2,519.35 = 639.78/x
  3. Step 3: Cross multiply
    1,678.82x = 2,519.35 × 639.78
  4. Step 4: Simplify right side
    1,678.82x = 1,611,829.74
  5. Step 5: Solve for x
    x = 1,611,829.74/1,678.82
  6. Step 6: Final answer
    x = 960.10

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1.5x scale

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.