Let me start from the meaning of half plane.you must have learned that there are two axes X and Y axes which includes positive X axes and negative X axes and there is positive Y axes and negative y axes. So there are four quadrants which i have explained in the figure. I have explained the meaning of Half plane in the Diagram also. Half plane=Figure obtained by covering any two adjacent regions of the coordinate axes.So we get four half planes.
Now your question is k is a half plane determined by QR, such that 0<x≤180 and there is exactly one ray QRP that lies in k
So, 
Answer:
Value of x = -7
Step-by-step explanation:
Given:
First angle = 83°
Second angle = 24°
Third angle = (38 - 5x)°
Find:
Value of x
Computation:
We know that sum of all interior angle in triangle is 180°
So,
83 + 24 + 38 - 5x = 180
145 - 5x = 180
-5x = 35
x = -7
Value of x = -7
Answer: Read below.
Step-by-step explanation:
1) V = 84.82 Estimate: 85
2) V = 564.44 Estimate: 564
3) V = 4712.39 Estimate: 4712.4
See the attached diagram.
In the right triangle, x is opposite the 23.6 degree angle, and the adjacent side is 250 m. This suggests using the tangent ratio.

Finally, to get the height of the tree, add Sarah's height, 1.5 m.
The tree is approximately 110.7m tall.
90/2=45
45/3=15
15/3=5
90=2*3*3*5=2¹*3²*5¹