Answer:
E
Step-by-step explanation:
The problem says that triangle BDC lies in the plane k, which means that whatever angle is formed by another point beyond this plane with any of the three segments that form BDC (BD, DC, and BC) is the same as the angle formed by the line connecting the point and the plane.
Here, we're given that AD⊥DC, which means AD forms a 90° angle with DC. Then, since DC is already on the plane, we already know for sure that AD is definitely perpendicular to plane k.
Thus, the answer is E (none of these).
A= bh divide by 2 so you'll multiply 10x8 the product would be 80 and so you divide 80 by 2 and get 40 as your result.
a = amount invested at 5%
b = amount invested at 2%
now, we know the total invested by Mr Wilson was 20000, so whatever "a" and "b" might be, we know that a + b = 20000.
![a + b = 20000\implies b = 20000-a \\\\[-0.35em] ~\dotfill\\\\ \stackrel{\textit{5\% of a}}{\left( \cfrac{5}{100} \right)a}\implies 0.05a~\hfill \stackrel{\textit{2\% of b}}{\left( \cfrac{2}{100} \right)a}\implies \begin{array}{llll} 0.02b\\\\ \stackrel{substituting}{0.02(20000-a)} \end{array}](https://tex.z-dn.net/?f=a%20%2B%20b%20%3D%2020000%5Cimplies%20b%20%3D%2020000-a%20%5C%5C%5C%5C%5B-0.35em%5D%20~%5Cdotfill%5C%5C%5C%5C%20%5Cstackrel%7B%5Ctextit%7B5%5C%25%20of%20a%7D%7D%7B%5Cleft%28%20%5Ccfrac%7B5%7D%7B100%7D%20%5Cright%29a%7D%5Cimplies%200.05a~%5Chfill%20%5Cstackrel%7B%5Ctextit%7B2%5C%25%20of%20b%7D%7D%7B%5Cleft%28%20%5Ccfrac%7B2%7D%7B100%7D%20%5Cright%29a%7D%5Cimplies%20%5Cbegin%7Barray%7D%7Bllll%7D%200.02b%5C%5C%5C%5C%20%5Cstackrel%7Bsubstituting%7D%7B0.02%2820000-a%29%7D%20%5Cend%7Barray%7D)
now, we know the total of earned interest is 550 bucks, so then
