Answer:
z = 30
Step-by-step explanation:
so your going to do a ratio to the big triangle to small
ratio be z+10 over 52 to 10 over 13
cross multiply 52 x 10 = 13(z+10)
520 = 13z + 130 subtract 130 from both sides
13z = 390 divide by 13 to get z = 30
