Answer:
Please see the attached pictures for full solution.
The answer would be hydro power because of its waterfalls
<em>P = a + b + c = 49 cm</em>
<em>a = b + 7 => b = a - 7</em>
<em>a = c - 5 => c = a + 5</em>
<em>_____________________</em>
<em>a + (a - 7) + (a + 5) = 49</em>
<em>3a = 49 + 7 - 5</em>
<em>3a = 51 </em>
<em>a = 17 cm</em>
<em>b = 17 - 7 = 10 cm</em>
<em>c = 17 + 5 = 22 cm</em>