28
Explanation:
a^2=b^2+c^2-2bc\cos A
a
2
=b
2
+c
2
−2bccosA
From reference sheet.
s^2 = 34^2+16^2-2(34)(16)\cos 56
s
2
=34
2
+16
2
−2(34)(16)cos56
Plug in values.
s^2 = 1156+256-2(34)(16)(0.559193)
s
2
=1156+256−2(34)(16)(0.559193)
Square and find cosine.
s^2 = 1156+256-608.40188
s
2
=1156+256−608.40188
Multiply.
s^2 = 803.59812
s
2
=803.59812
Add.
s=\sqrt{803.59812} \approx28.348 \approx28
s=
803.59812
≈28.348≈28