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Finding the Fourth Proportional to 1,946, 2,919.31 and 647.78

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Solution

The fourth proportional to 1,946, 2,919.31 and 647.78 is: 971.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,946 : 2,919.31 = 647.78 : x
  2. Step 2: Convert to fraction form
    1,946/2,919.31 = 647.78/x
  3. Step 3: Cross multiply
    1,946x = 2,919.31 × 647.78
  4. Step 4: Simplify right side
    1,946x = 1,891,056.04
  5. Step 5: Solve for x
    x = 1,891,056.04/1,946
  6. Step 6: Final answer
    x = 971.77

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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.