Answer:
36 ft.
Step-by-step explanation:
The given perimeter of triangle EDF is 12, in which the hypotenuse is 5. This means that it is a 3-4-5 triangle, meaning that ED = 3, DF = 4, EF = 5.
It is given that BC (the other triangle's hypotenuse) is 15. This means that the left triangle is to the scale factor of 3 of triangle EDF. Therefore, multiply 3 to all sides measurements, and then add all the sides to get the perimeter.
Hypotenuse: 5 x 3 = 15
Leg 1: 4 x 3 = 12
Leg 2: 3 x 3 = 9
Perimeter: 15 + 12 + 9 = 36
36 ft. is your answer.
A reflection over the line y=x implies exchanging the x and y coordinates of a point. For example if you take a generic point (a,b) then its reflection over y=x is (b,a). Our point is (-1,3) so its reflection over y=x is the point (3,-1).
Then we have to translate it two units left. Translating a point left means that we are moving towards negative x values so we need to substract 2 from the x coordinate:

Finally we have to translate it 1 unit up towards positive y values so we have to add 1 to its y coordinate:

And these are the final coordinates. In the following picture you have the points you get after each step (from A to D) with the y=x line in blue:
2. x = 1/4 ( 0.25)
4. y = 122, x = 42
6. x = 63, y = 8
8. is missing
10. 13.5 cm
12. x = 10.6
14. x = 5.45
I guess you are asking to find the sum of the first 8 terms. If so, then:
Sum = a₁(1-rⁿ)/(1-r), where a₁ is the 1st term, r=common ratio and n=number of terms:
the 1st term a₁ =3
common ratio r = - 2 (since -6/3 = - 2, and 12/-6 = - 2, etc.)
Sum = 3[(1- (-2)⁸]/(1-2) = 3(1- 256)/(1/2)
Sum = -1530