This triangle has base 16 therefore the sides must be 17cm and 17 cm
When we make a altitude it divides it into two right triangles and there is a property in which the altitude of the isoceles triangle divides the base in 2 equal halves
So the side of the right triangle will be x , 8 , 17
Using pythgoreus theorem
x²+8²=17²
x = √225
x = 15
So the altitude is 15 cm
Must click thanks and mark brainliest