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Finding the Fourth Proportional to 815.06, 1,221.50 and 687.62

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Solution

The fourth proportional to 815.06, 1,221.50 and 687.62 is: 1,030.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.06 : 1,221.50 = 687.62 : x
  2. Step 2: Convert to fraction form
    815.06/1,221.50 = 687.62/x
  3. Step 3: Cross multiply
    815.06x = 1,221.50 × 687.62
  4. Step 4: Simplify right side
    815.06x = 839,927.83
  5. Step 5: Solve for x
    x = 839,927.83/815.06
  6. Step 6: Final answer
    x = 1,030.51

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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.