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Finding the Fourth Proportional to 1,980.78, 2,970.16 and 664.08

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Solution

The fourth proportional to 1,980.78, 2,970.16 and 664.08 is: 995.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,980.78 : 2,970.16 = 664.08 : x
  2. Step 2: Convert to fraction form
    1,980.78/2,970.16 = 664.08/x
  3. Step 3: Cross multiply
    1,980.78x = 2,970.16 × 664.08
  4. Step 4: Simplify right side
    1,980.78x = 1,972,423.85
  5. Step 5: Solve for x
    x = 1,972,423.85/1,980.78
  6. Step 6: Final answer
    x = 995.78

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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.