If Jane walks north for 3 miles, turns 45∘ to the right, and then walks another 4miles, how many miles will Jane be from her starting point? Give your answer as a decimal rounded to the nearest hundredth.

1 Answer
May 23, 2018

2.83 miles

Explanation:

The law of cosines says that when finding an unknown side of a non-right triangle, we can use the other two sides such that:

b^2=a^2+c^2-2(a)(c)(cosB)b2=a2+c22(a)(c)(cosB)

Since we are given the angle corresponding to (or facing) the unknown side measure, we can use our formula such that:

b^2=3^2+4^2-2(3)(4)(cos45)b2=32+422(3)(4)(cos45)
b^2=9+16-24(cos45)b2=9+1624(cos45)
b^2=25-17b2=2517
b^2=8b2=8
b=sqrt(8)b=8
b=2.83" miles"b=2.83 miles