Question

In △DEF, what is the length of DF ?

A. 90
B. 45 sqrt 2
C. 15 sqrt 3
D. 30 sqrt 3

Answer 1

30 square root 3

Answer 2

if you don't know trigonometry use the properties of a semi-equilateral triangle

Answer 3

do you know the rule of sinus of an angle inside a right triangle ?

Answer 4

so then if you will us this rule so than you will can writing

sinus 60 = DE / DF

...because you know the sin 60 = ? hope you know this --- so than from this you will can calcule very very easy the length of DF

Answer 5

ohh thanks :DD

Answer 6

ok !

good luck

bye