we have
c=t+11 -----> hypotenuse
a=t+10 ----> leg
b=t-7 -----> other leg
step 1
Apply the Pythagorean Theorem
c^2=a^2+b^2
(t+11)^2=(t+10)^2+(t-7)^2
t^2+22t+121=t^2+20t+100+t^2-14t+49
combine like terms
t^2+22t+121=2t^2+6t+149
the left side is not equal to the right side
that means
the given lengths, not satisfy the pythagorean Theorem
Is not a right triangle
The perimeter is equal to
P=(t+11)+(t+10)+(t-7)
P=(3t+14) units
therefore
I not agree with Susan's diagram
I not agree with perimeter formula
I not agree with algebraic response
A claim-----> if the triangle is a right triangle, then, must satisfy the Pythagorean Theorem