Answer:
yes
Step-by-step explanation:
Hello There!
In order for a right triangle to be a right triangle the hypotenuse ( longest side) squared must equal the sum of the two shorter sides squared
so if this is a right triangle then
[tex]21^2+28^2=35^2\\21^2=441\\28^2=784\\784+441=1225\\35^2=1225\\1225=1225[/tex]
so as you can see 21^2+28^2 does = 35^2 so the side measures given do make a right triangle