5
E
3
9
F
Heron's formula: Area = √√s(sa)(sb)(s-c)
What is the area of triangle DEF?
O 2√2 square units
O2/14 square units
O 6/22 square units
O12√77 square units
HELPPP

5 E 3 9 F Herons formula Area ssasbsc What is the area of triangle DEF O 22 square units O214 square units O 622 square units O1277 square units HELPPP class=

Respuesta :

Answer:

  (b)  2√14 square units

Step-by-step explanation:

You want the area of a triangle with side lengths 3, 5, 6 units.

Heron's formula

Heron's formula for the area of a triangle makes use of the "semiperimeter", s. For this triangle, that is ...

  s = (3 +5 +6)/2 = 7

Then the area is given by ...

  A = √(s(s -a)(s -b)(s -c)) = √(7(7 -3)(7 -5)(7 -6)) = √(7·4·2·1)

  A = 2√(7·2) = 2√14

The area of triangle DEF is 2√14 square units, choice B.