well, a right-triangle has 90° total, so if one of the acute angles is taking up 74°, then the other is just 90° - 74°.
When two triangles are similar, they're sides are in proportion.
In order to find the unknown side, we first have to find the ratio of the larger triangle to the smaller triangle.
We can use the sides TV and LN to make the proportion.
= 
The ratio between the two triangles is 21:6
Now we can solve for the unknown side.
= 
Cross multiply:
8 * 21 = 6 * LM
168 = 6LM
Divide both sides by 6:
LM = 28
The unknown side's length is 28 centimeters
Good luck!
- - Let's solve for C.
Starting off with our equation:

Transform:

Solve for that:

Solve for that for the last time and your answer is
Answer:
Rectangle C
Step-by-step explanation:
i just had this question and got it right