1 7/8 tons of sand will be required to fill the playground
The answer to this question is 2 square root 26
<span>Solve this by substitution:
</span>Solve 5x - 4y = -13 for x:<span><span><span><span>5x </span>− <span>4y </span></span>+ <span>4y </span></span>= -<span>13 + <span>4y </span></span></span>(Add 4y to both sides)
<span><span><u>5x </u></span>= <span><span><u>4y - </u><u>13 </u></span><u> </u> </span></span>(Divide both sides by 5)
5 5
<span>x = <span><span><span><u>4</u></span> y </span>+ -<span><u>13</u><span>
</span></span></span></span> 5 5
You can use https://www.mathpapa.com/algebra-calculator.html
5x - 4y = -13, 8x +10y = 12 (enter both equations with a comma between them and it will solve for you and show you step by step.
Answer:
Part 1)
Bob's mistake was to have used the cosine instead of the sine
The measure of the missing angle is 
Part 2) The surface area of the pyramid is 
Step-by-step explanation:
Part 1)
Let
x----> the missing angle
we know that
In the right triangle o the figure
The sine of angle x is equal to divide the opposite side angle x to the hypotenuse of the right triangle


Bob's mistake was to have used the cosine instead of the sine
Part 2) we know that
The surface area of the square pyramid is equal to the area of the square base plus the area of its four lateral triangular faces
so
![SA=b^{2}+4[\frac{1}{2}(b)(h)]](https://tex.z-dn.net/?f=SA%3Db%5E%7B2%7D%2B4%5B%5Cfrac%7B1%7D%7B2%7D%28b%29%28h%29%5D)
where
b is the length side of the square
h is the height of the triangular lateral face
In this problem
-------> by an 45° angle
so



Find the value of b

Find the surface area
![SA=12^{2}+4[\frac{1}{2}(12)(6)]=288\ cm^{2}](https://tex.z-dn.net/?f=SA%3D12%5E%7B2%7D%2B4%5B%5Cfrac%7B1%7D%7B2%7D%2812%29%286%29%5D%3D288%5C%20cm%5E%7B2%7D)
Answer:
False
Step-by-step explanation: