Answer:
Solved using the <u>Exterior angle theorem</u>.
2x-5+x-17 = 128
3x-22 = 128
3x = 150
x = 50
Notice the tickmark on the angles, those angles are equal to each other.
now, notice the angle at the very top, the large triangle is really sharing it with smaller-inscribed triangle, and therefore is equal on both triangles.
therefore, the larger triangle, is similar with smaller-inscribed triangle by AA.
what the dickens does that mean?
Answer: 240
Step-by-step explanation:
144/3 = 48
5x48= 240
The answer is B.C. =8.1cm
The working is on the picture