Resposta:

Explicação passo a passo:

a.

30²=10²+x²

900=100+x²

x²=900-100

x²=800

x=√800

x=20√2

sen ∝= 10/30=1/3

cos ∝ = 20√2/30=2√2/3

tg∝ =10/20√2 .√2/√2=10√2/20√4=10√2/40=√2/4

b.

x²=9²+12²

x²=81+144

x²=225

x=√225

x=15

sen ∝ =9/15=3/5

cos ∝ = 12/15= 4/5

tg ∝ = 9/12=3/4

c.

17²=8²+x²

289=64+x²

x²=289-64

x²=225

x=√225

x=15

sen ∝ =15/17

cos ∝ = 8/17

tg ∝ = 15/8