Answer:
270
Step-by-step explanation:
37 % of a number is the same as divide by 100 and multiply by 37. To get this number we do the opposite: divide 99.9 by 37 which gives us 27 and then multiply by 100 which will give us 270.
if we check this: 270 /100 *37 = 99,9
C
Use the formula of the Pythagorean theorem. a^2 + b^2 = c^2
a = 11.5
b = 18
11.5^2 + 18^2 = 456.25^2
Sqrt(456.25) to find c
c=21.36 in.
Based on the picture, we know that ED is equal to DB. Therefore:
2 times ED=EB
2(10)=20
EB is 20
Take the augmented matrix,
![\left[\begin{array}{ccc|c}2&1&-3&-20\\1&2&1&-3\\1&-1&5&19\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Cc%7D2%261%26-3%26-20%5C%5C1%262%261%26-3%5C%5C1%26-1%265%2619%5Cend%7Barray%7D%5Cright%5D)
Swap the row 1 and row 2:
![\left[\begin{array}{ccc|c}1&2&1&-3\\2&1&-3&-20\\1&-1&5&19\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Cc%7D1%262%261%26-3%5C%5C2%261%26-3%26-20%5C%5C1%26-1%265%2619%5Cend%7Barray%7D%5Cright%5D)
Add -2(row 1) to row 2, and -1(row 1) to row 3:
![\left[\begin{array}{ccc|c}1&2&1&-3\\0&-3&-5&-14\\0&-3&4&22\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Cc%7D1%262%261%26-3%5C%5C0%26-3%26-5%26-14%5C%5C0%26-3%264%2622%5Cend%7Barray%7D%5Cright%5D)
Add -1(row 2) to row 3:
![\left[\begin{array}{ccc|c}1&2&1&-3\\0&-3&-5&-14\\0&0&9&36\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Cc%7D1%262%261%26-3%5C%5C0%26-3%26-5%26-14%5C%5C0%260%269%2636%5Cend%7Barray%7D%5Cright%5D)
Multiply through row 3 by 1/9:
![\left[\begin{array}{ccc|c}1&2&1&-3\\0&-3&-5&-14\\0&0&1&4\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Cc%7D1%262%261%26-3%5C%5C0%26-3%26-5%26-14%5C%5C0%260%261%264%5Cend%7Barray%7D%5Cright%5D)
Add 5(row 3) to row 2:
![\left[\begin{array}{ccc|c}1&2&1&-3\\0&-3&0&6\\0&0&1&4\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Cc%7D1%262%261%26-3%5C%5C0%26-3%260%266%5C%5C0%260%261%264%5Cend%7Barray%7D%5Cright%5D)
Multiply through row 2 by -1/3:
![\left[\begin{array}{ccc|c}1&2&1&-3\\0&1&0&-2\\0&0&1&4\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Cc%7D1%262%261%26-3%5C%5C0%261%260%26-2%5C%5C0%260%261%264%5Cend%7Barray%7D%5Cright%5D)
Add -2(row 2) and -1(row 3) to row 1:
![\left[\begin{array}{ccc|c}1&0&0&-3\\0&1&0&-2\\0&0&1&4\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Cc%7D1%260%260%26-3%5C%5C0%261%260%26-2%5C%5C0%260%261%264%5Cend%7Barray%7D%5Cright%5D)
So we have 
.
