Question

Please answer it now in two minutes

Answer 1

Answer:

$f = 10.7$

Step-by-step explanation:

Given ∆DEF,

<F = 36°

DF = e = 15

EF = d = 6

DE = f = ?

f can be found using the Law of Cosine as shown below:

$f^2 = d^2 + e^2 - 2(d)(e)*cos(F)$

Plug in your values:

$f^2 = 6^2 + 15^2 - 2(6)(15)*cos(36)$

Evaluate:

$f^2 = 36 + 225 - 180*0.809$

$f^2 = 261 - 145.62$

$f^2 = 115.38$

$f = 10.74$

$f = 10.7$ (to nearest tenth)