Step-by-step explanation:
angle A and Angle D are congruent. as are Angle C and Angle F.
because you have two pairs of congruent angles this proves the triangles are similar using AA Theorem.
I couldn't read the 3rd question. if you post as a comment I can look at it better.
Answer: We are missing some data here, but it appears to be a right triangle question. Assuming that triangle ABC is a right triangle, the measure of angle B would be about 63.26 degrees.
If you draw a right triangle ABC with the given information, you will see that we have an adjacent side and hypotenuse with regard to angle B.
Therefore, we can write and solve the following cosine ratio.
cos(B) = 9/20
B = 63.26 degrees
7² + 10² = c² where c = hypotenuse
49 + 100 = c²
149 = c²
c = √149 feet