Answer:
Part 1) The perimeter is 
Part 2) The diagonal is 
Step-by-step explanation:
<u><em>The question in English is</em></u>
You have a rectangle whose base is twice the height and its area is 12
square centimeters. Calculate the perimeter of the rectangle and its diagonal
step 1
Find the dimensions of rectangle
we know that
The area of rectangle is equal to


so
----> equation A
The base is twice the height
so
----> equation B
substitute equation B in equation A

Find the value of b

step 2
Find the perimeter of rectangle
The perimeter is given by

substitute

step 3
Find the diagonal of rectangle
Applying the Pythagorean Theorem

substitute


