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Finding the Fourth Proportional to 1,942.80, 2,912.40 and 643.56

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Solution

The fourth proportional to 1,942.80, 2,912.40 and 643.56 is: 964.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,942.80 : 2,912.40 = 643.56 : x
  2. Step 2: Convert to fraction form
    1,942.80/2,912.40 = 643.56/x
  3. Step 3: Cross multiply
    1,942.80x = 2,912.40 × 643.56
  4. Step 4: Simplify right side
    1,942.80x = 1,874,304.14
  5. Step 5: Solve for x
    x = 1,874,304.14/1,942.80
  6. Step 6: Final answer
    x = 964.74

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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.