What is the perimeter of triangle DEF?

A 10.4 units
B 2.4 units
C 4.2 units
D. 12.2 units
HELP PlZ

Given:

Triangle DEF

To find:

The perimeter of triangle DEF.

Solution:

Coordinate of D = (-1, 1)

Coordinate of E = (2, 1)

Coordinate of F = (-1, 4)

Distance formula:

Distance of DE:

Here,

d = 3 units

Distance of EF:

Here,

d = 4.2 units

Distance of FD:

Here,

d = 3 units

Perimeter of ΔDEF = DE + FE + FD

                                = 3 + 4.2 + 3

                                = 10.2 units

The perimeter of triangle DEF is 10.2 units.

the answer is b.

step-by-step explanation:

by the trigonometric ratio tangent, tangent equals opposite divided by adjacent.

therefore, tan(50) equals ac/3

multiply each side by 3 to get: ac=3tan(50)

the answer is b.