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Finding the Fourth Proportional to 1,095.78, 1,640.40 and 663.78

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Solution

The fourth proportional to 1,095.78, 1,640.40 and 663.78 is: 993.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,095.78 : 1,640.40 = 663.78 : x
  2. Step 2: Convert to fraction form
    1,095.78/1,640.40 = 663.78/x
  3. Step 3: Cross multiply
    1,095.78x = 1,640.40 × 663.78
  4. Step 4: Simplify right side
    1,095.78x = 1,088,864.71
  5. Step 5: Solve for x
    x = 1,088,864.71/1,095.78
  6. Step 6: Final answer
    x = 993.69

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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.