Answer:
The surface area is equal to 
Step-by-step explanation:
The surface area of the triangular pyramid is equal to the area of its four triangular faces
so
In this problem
![SA=4[\frac{1}{2}(b)(h)]](https://tex.z-dn.net/?f=SA%3D4%5B%5Cfrac%7B1%7D%7B2%7D%28b%29%28h%29%5D)
we have


substitute the values
![SA=4[\frac{1}{2}(15)(13)]=390\ in^{2}](https://tex.z-dn.net/?f=SA%3D4%5B%5Cfrac%7B1%7D%7B2%7D%2815%29%2813%29%5D%3D390%5C%20in%5E%7B2%7D)
Answer:
Step-by-step explanation: The amount of water is the dependent value
Ax^2+bx=c
REMEMBER THIS
ok
first, make sure that a is 1
done
now take 1/2 of b and square it
-18/2=-9, (-9)^2=81
add that to both sides
x²-18x+81=19+81
x²-18x+81=99
factor perfect square
(x-9)²=100
square root both sides
don't forget positive and negative root
x-9=10
x-9=-10
ad 9 to both sides
x=19
x=-1
answer is -1; 19
2nd choice is answer
The slope of the tangent line to
at
is given by the derivative of
at that point:

Factorize the numerator:

We have
approaching -1; in particular, this means
, so that

Then

and the tangent line's equation is

<em><u>ANSWER</u></em>
Let the width be y
2(L + W) = Perimeter
2(2y - 5cm + y) = 62cm
(2×2y) + (2×-5cm) + (2×y) = 62cm
4y + - 10cm + 2y = 62cm
4y - 10cm + 2y = 62cm
4y + 2y - 10cm = 62cm
6y - 10cm + 10cm = 62cm + 10cm
<u>6</u><u>y</u> = <u>7</u><u>2</u><u>c</u><u>m</u>
6 6
y = 12cm
<em><u>WIDTH</u></em>
= y
= 12cm
<em><u>LENGTH</u></em>
= 2y - 5cm
= 2×y - 5cm
= 2×12cm - 5cm
= 24cm - 5cm
= 19cm
<em><u>Providence</u></em>
19cm + 19cm + 12cm + 12cm = 62cm which is the perimeter