Let the equal sides of the isosceles Δ ABC be x.
Given that the perimeter of Δ ABC = 50m.
Therefore, 2x + AC = 50 --- (1)
It is also given that the perimeter of Δ ABD = 40m.
Therefore, x + BD + AD = 40
BD is the median of the Δ ABC. Therefore, D is the midpoint of AC.
So AD = CD.
Or, AD =
AC
Therefore, 
Multiply both sides by 2.
2x + 2BD + AC = 80
From (1), 2x + AC = 50.
Therefore, 2BD + 50 = 80
2BD = 80 - 50
2BD = 30
BD = 15m.
Answer:
-6 - square root 31, -6 + square root 31
Yes, they are.
If the triangles have three corresponding angles equal means that they are either similar or congruent.
The definition of congruent means that the sides have the same length. That is precisely what the statement says.
So, being the lengths of the corresponding angles the same the two triangles are identical, this is they are congruent.
The formula for a diagonal of a rectangle is <span>√w^2+h^2, with w and h being the width and height. Plug in your numbers to get </span><span>√7^2+5.5^2. Simplify that into </span><span>√49+30.25, then to </span><span>√79.25. Use your calculator to get 8.9022. The diagonal is 8.9 feet.</span>