Answer:
Option B. 
Step-by-step explanation:
step 1
Find the central angle of the shaded sector
Remember that the diameter divide the circle into two equal parts ( 180 degrees each part)
so
Let
x -----> the measure of the central angle of the shaded sector
∠x+72°=180°
∠x=180°-72°=108°
step 2
Find the area of the circle
The area of the circle is

we have

assume

substitute


step 3
Find the area of the shaded sector
Remember that the area of the complete circle subtends a central angle of 360 degrees
so
by proportion find the area of a sector by a central angle of 108 degrees

Answer:
12+27a
Step-by-step explanation:
3(4+9a)=3(4)+3(9a)=12+27a
Answer:



Step-by-step explanation:
Given

Required
Determine: 
Solving for
, we have:
--- angle on a straight line
So, we have:



To solve for
, we have:

--- Vertically opposite angles
So:


From X + Y = 4
<span>Y = 4 - X </span>
<span>Substituite this for Y in 2X - Y = 2 to get </span>
<span>2X -(4 - X ) = 2 </span>
<span>2X -4 +X = 2 </span>
<span>3X = 6 </span>
<span>X = 2 </span>
<span>Now return to X + Y = 4 </span>
<span>Knowing X = 2, </span>
<span>2 + Y = 4 </span>
<span>Y = 4 - 2 </span>
<span>Y = 2 </span>
<span>The solution is (X,Y) = (2,2) </span>
<span>This is quadrant I </span>
<span>Answer is A</span>
Answer:
19/100 or 5/26
Step-by-step explanation:
i think