DEF, find the length of d, to the nearest tenth, given that ∠D=110o, e = 10cm and f = 14cm.

Sagot :

Answer:

d = 19.8 cm

Step-by-step explanation:

Use the law of cosines

[tex]d^{2} = e^{2} + f^{2} -2ef cos D\\d^{2} = 10^{2} + 14^{2} -2(10)(14) cos 110\\[/tex]

    = 100 + 196 - 280 cos 110

    = 296 - (-95.765640)

    = 391.765640

[tex]d = \sqrt{391.7656401}[/tex]

  d = 19.8 cm