Answer:
40.6°
Step-by-step explanation:
formula of area of triangle
1) √[(s)(s-a)(s-b)(s-c)] , s= (a+b+c)/2
2) 1/2ab sin c
calculate the area first
s= (9.6+6.3+8.1)/2
=12
area= √[(12)(12-9.6)(12-6.3)(12-8.1)]
= √640.224
= 25.3026
1/2(9.6)(8.1) sin c = 25.3026
sin c = 25.3026(2)/(9.6*8.1)
sin c = 0.6508
c = sin-¹ 0.6508
c = 40.6 (nearest tenth)
