Special right triangles.
Find u.
Please help due in 30 min!!

2 km

Step-by-step explanation:

use the 45-45-90 triangle formula to find u.

Answers:

6)  The number, "8.2", belongs to:

[C]:  "rational numbers only" .

Explanation:  

Choice [A]:  "whole number only" ; is incorrect; since any decimal value/ decimal-containing value — including this given value: "8.2" — is not a "whole number" ; and NOT an integer.

Thus, we can eliminate Choices: [D]: and [B] ; and we are left with:
  "Choice:  [C]:  "Rational numbers only".

Note:  "8.2" is a rational number;  since the number is real; and since the number is not "irrational".  An "irrational number" would mean that the resulting decimal form would be "non-terminating" AND "non-repeating".   

→ As such:  Answer choice:  [C]:  "rational numbers only".


7)  The number, "5", belongs to:

    [D]:  "integers, whole numbers, and rational numbers".

Explanation:

Choice:  [A]:  is:  "whole numbers ONLY".  This COULD be correct; since "5" is a whole number;  but take note of the the word: "only" in this answer choice.

Choice:  [B]:  is:  "integers and rational numbers".  Yes; "5" is both an "integer"; AND a "rational number";  and there is no word, such as "only" in this answer choice.  So, this answer could be correct;  and arguably is a better answer than "Choice: [A]" .
→ So; at this point, let us "tentatively eliminate":  "Answer choice: [A] " .

Choice: [C]: is:  "rational numbers only".  Note that:  "5" ; is, in fact, a "rational number"; however, take note of the word:  "only";  (as mentioned in:  "Answer choice:  [A]" . 
→ At this point, "Answer choice: [B]: is arguably a better answer than choices:  [A} & [C].    
→ So; we can tentatively eliminate choices: [A] & [C].

Choice [D]:  is:  "integers, whole numbers, and rational numbers" .

→ This choice is the best answer choice given;  since "5" ;  is an integer, a whole number, AND a rational number.


8)  The number, "-27", belongs to:

    [B]:  "integers and rational numbers".

Explanation:

Choice: [A]:  "whole number only" ; is incorrect, because negative numbers; including our given value;  "- 27 " ;  is NOT a "whole number".

             →  As such, we can eliminate:
   "Choice [A]" ;
    as well as:  "Choice [D]:  "integers, whole numbers, and rational numbers". 

We are left with:  "Choices:  [B]  and [C] " .

Choice [B]:  is: "integers and rational numbers".  This choice could be correct; since our given value; " -27 " ; is both an "integer" AND a "rational number".

Choice [C]: is: "rational numbers only".  Our given value, "-27", is a rational number;  however, note the word: "only" ; in this answer choice.

   → Choice [B]:  is:  "integers AND rational numbers" ; which is the best—and correct—answer choice.