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Finding the Fourth Proportional to 1,980, 2,970 and 612

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Solution

The fourth proportional to 1,980, 2,970 and 612 is: 918

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,980 : 2,970 = 612 : x
  2. Step 2: Convert to fraction form
    1,980/2,970 = 612/x
  3. Step 3: Cross multiply
    1,980x = 2,970 × 612
  4. Step 4: Simplify right side
    1,980x = 1,817,640
  5. Step 5: Solve for x
    x = 1,817,640/1,980
  6. Step 6: Final answer
    x = 918

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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.