Question

Use the law of cosines to find the length of side c. With a triangle with side b= 21cm and side a= 15cm and angle C= 23

Answer 1

c= 9.28 cm

Explanation:

c^2 =a^2 + b^2 - 2abcosC law of cosines

c^2 = 15^2 + 21^2 - 2*15*21 * cos23

c^2=225+441-630 *.9205

combine like terms

c^2 =666 - 86.08579.92

c^2 =86.09

take the square root of each side

sqrt(c^2) = sqrt(86.09)

c = 9.28