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Finding the Fourth Proportional to 859.72, 1,290.99 and 815.89

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Solution

The fourth proportional to 859.72, 1,290.99 and 815.89 is: 1,225.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    859.72 : 1,290.99 = 815.89 : x
  2. Step 2: Convert to fraction form
    859.72/1,290.99 = 815.89/x
  3. Step 3: Cross multiply
    859.72x = 1,290.99 × 815.89
  4. Step 4: Simplify right side
    859.72x = 1,053,301.75
  5. Step 5: Solve for x
    x = 1,053,301.75/859.72
  6. Step 6: Final answer
    x = 1,225.18

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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.