Can anyone explain how to do this?

Step-by-step explanation:
Using the equation [tex]a^{2} + b^{2} = c^{2}[/tex]
so [tex]a^{2} = 35[/tex] and [tex]b^{2} =50[/tex]
[tex]a^{2} + b^{2} = 85^{2}[/tex]
Answer:
85 units²
Step-by-step 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.
The hypotenuse is the side opposite the right angle ( third side ) , then
area = 35 + 50 = 85 units²