Step-by-step explanation:
look at the picture !
she has to paint actually 6 rectangles :
the 3 tops of the 3 stairs.
and the 3 vertical front boards (the front of each step of the stairs).
what is the area of these rectangles ? summing up all 6 - that is the surface area to be painted.
each top rectangle is clearly
82×19 (19 cm deep) = 1558 cm²
each front board is
82×12 (12 cm high) = 984 cm²
so, in total we have
3×1558 + 3×984 = 4674 + 2952 = 7626 cm²
as surface area to be painted.
Answer:
Step-by-step explanation:

Answer:
k = -9.
Step-by-step explanation:
As the triangle is right-angled at Q, by Pythagoras:
PR^2 = PQ^2 + RQ^2
So, substituting the given data and using the distance formula between 2 points:
(7 - 1)^2 + (k - 4)^2 = (-4-4)^2 + (-3-1)^2 + (7 - (-3))^2 + (k - (-4))^2
36 + (k - 4)^2 = 64 + 16 + 100 + ( k + 4)^2
(k - 4)^2 - (k + 4)^2 = 180 - 36
k^2 - 8k + 16 - (k^2 + 8k + 16) = 144
-16k = 144
k = -9.
So the answer is 30 packages but I did 25 times 20 = 500 and then 25 times 10 = 250
So. 30 = 750