Respuesta :

Answer:

15 units

Step-by-step explanation:

By using the Pythagoras Theorem,

C^2 = A^2 + B^2

Substitute in the given values,

25^2 = a^2 + 20^2

625 = a^2 + 400

625 - 400 = a^2 + 400 - 400

a^2 = 225

[tex]a = \sqrt{225} [/tex]

= 15

Hope this too helped! ^^

I'd recommend watching a video or two on the topic of Pythagoras Theorem, if this explanation isn't clear enough.