Answer:
[tex]3.5[/tex]
Step-by-step explanation:
The smallest side of a triangle is formed by the smallest angle in the triangle.
To find the side opposite (formed by) the 20 degree angle, we can use the Law of Cosines. The Law of Cosines states that for any triangle, [tex]c^2=a^2+b^2-ab\cos \gamma[/tex], where [tex]a[/tex], [tex]b[/tex], and [tex]c[/tex] are the three sides of the triangle and [tex]\gamma[/tex] is the angle opposite to [tex]c[/tex].
Let [tex]c[/tex] be the side opposite to the 20 degree angle.
Assign variables:
Substituting these variables, we get:
[tex]c^2=4^2+7^2-2(4)(7)\cos 20^{\circ},\\c^2=16+49-56\cos 20^{\circ},\\c^2=12.377213236,\\c=\sqrt{12.377213236}=3.51812638147\approx \boxed{3.5}[/tex]
Therefore, the shortest side of this triangle is 3.5.
