What’s the exact area of triangle DEF shown in the graph?

A(t) = 19 u²

Step-by-step explanation:

Area of a triangle is  b*h/2  (base times height divided by 2)

The graph shows a right triangle  which height is the segment EF which s parallel to vertical axis  then its length could be determined by simple inspection  looking at how many units it is (6)

For the base, we have to look at the projections over the y and x axis they are: over y = 2  and over x axis is 6

Then by Pitagoras  theorem, we get

ED = √ (2)² + (6)²        ⇒   ED = √40

ED = 2*√10  and

A(t) = (1/2)* 6*2*√10

A(t) = 6*√10   square units

A(t) = 18,97 u²

approximate to the nearest integer

A(t) = 19 u²