Answer:
C
Explanation:
using Pythagoras' identity in the right triangle
the square on the hypotenuse is equal to the sum of the squares on the other 2 sides.
here hypotenuse is ED and the other sides are EF and DF , then
EF² + DF² = ED² ( substitute values )
EF² + 12² = 19²
EF² + 144 = 361 ( subtract 144 from both sides )
EF² = 217 ( take square root of both sides )
EF =
