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Finding the Fourth Proportional to 1,215.43, 1,821.62 and 666.65

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Solution

The fourth proportional to 1,215.43, 1,821.62 and 666.65 is: 999.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,215.43 : 1,821.62 = 666.65 : x
  2. Step 2: Convert to fraction form
    1,215.43/1,821.62 = 666.65/x
  3. Step 3: Cross multiply
    1,215.43x = 1,821.62 × 666.65
  4. Step 4: Simplify right side
    1,215.43x = 1,214,389.19
  5. Step 5: Solve for x
    x = 1,214,389.19/1,215.43
  6. Step 6: Final answer
    x = 999.15

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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.