<h3>
Answer:  226 degrees</h3>
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Explanation:
Notice the tickmarks on the segments in the diagram. This tells us that chords DC and CB are the same distance from the center. It furthermore means that DC and CB are the same length, and arcs DC and CB are the same measure
arc DC = arc CB
12x+7 = 18x-23
12x-18x = -23-7
-6x = -30
x = -30/(-6)
x = 5
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Use this x value to find the measure of arcs DC and CB
- arc DC = 12x+7 = 12*5+7 = 67
- arc CB = 18x-23 = 18*5-23 = 67
We get the same measure for each, which helps confirm we have the correct x value. 
The two arcs in question add to 67+67 = 134 degrees. This is the measure of arc DCB. Subtract this from 360 to get the answer
arc DAB = 360-(arc DCB) = 360-134 = 226 degrees
I'm using the idea that (arc DCB) + (arc DAB) = 360 since the two arcs form a full circle. 
 
        
        
        
1) The lengths of the other 2 sides are 51 feet. 
Isosceles triangles have at least 2 equal sides. The base is 60 feet, so we can assume that the other 2 sides are equal 
162 = 60 + 2x 
x = the equal sides of the triangle. 
162 - 60 = 102
102 = 2x 
Divided by 2
51 = x 
51 + 51 = 102. 102 + 60 = 162
2)
Pool 1: 311.38ft.
8*19.4 = 155.2
8 * 5.7 * 2 = 91.2
5.7 * 5.7 = 32.49/2 (because its a triangle) = 16.254*4 = 64.98
155.2 + 91.2 + 64.98 = 311.39
Pool 2: Either 863.94ft or 484 + 121πft
22 * 22 = 484
22/2 = 11, So, the radius of the half circle is 11
Circle area = (pi)r^2 
11*11 = 121
pi * 121 = 121pi 
Using 3.14 substitute: 3.14 * 121 = 379.94
379.94 + 484 = 863.94
Pool 3: 207ft
Rhombus area = pq/2 
18 * 12 = 216
216/2 = 108
11 * 18 = 198/2 = 99
99 + 108 = 207
 
        
             
        
        
        
Answer:
Step-by-step explanation:
3x - 3y = 3(x-y)
 
        
             
        
        
        
The pyramid is shown in the diagram below.
The pyramid is built from four congruent triangles and one square as the base
We have the side of the square, so the area is = 10×10 = 100
We need the height of the triangle to work out its area. We can find out by using the height of the pyramid and half of the length of the side of the square.
Using the Pythagoras rule
Height of triangle = 

Area of one triangle = 1/2×10×12=60
Surface area of the pyramid = 100 + (4×60) = 340 square inches
 
        
        
        
Answer:

Step-by-step explanation:
As I mentioned earlier with a single side (line), rotations do not change the size of something. Only dilations do that. This goes for both lines AND shapes. 
However, if the question said she dilated the piece, then yes, the length in inches would be different. However, rotation just changes the position and nothing happens to the length. 
Hope this helped!