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Finding the Fourth Proportional to 1,290.91, 1,935.51 and 666.61

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Solution

The fourth proportional to 1,290.91, 1,935.51 and 666.61 is: 999.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,290.91 : 1,935.51 = 666.61 : x
  2. Step 2: Convert to fraction form
    1,290.91/1,935.51 = 666.61/x
  3. Step 3: Cross multiply
    1,290.91x = 1,935.51 × 666.61
  4. Step 4: Simplify right side
    1,290.91x = 1,290,230.32
  5. Step 5: Solve for x
    x = 1,290,230.32/1,290.91
  6. Step 6: Final answer
    x = 999.47

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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.