77.5%
Change to decimal:-
77.5 ÷ 100 = 0.775
775/1000
31/40
77.5% = 31/40
Answer:
a. 125 degrees
b. 62 degrees
c. 58 degrees
d. 130 degrees
Step-by-step explanation:
I assume these are the inner angles of the polygons.
remember, for a polygon with n sides we can fully split it into n-2 triangles without overlap.
each of these triangles has an angle sum of 180 degrees.
to get the total inner angle sum of the polygon, we need to multiply 180 by (n-2) (= the number of triangles).
out of that total we can then calculate the size of the missing angle.
a. 6 sides, therefore 4 triangles
4×180 = 720 degrees
the missing angle is
angle = 720 - 88 - 152 - 125 - 105 - 125 = 125
b. 5 sides, 3 triangles
3×180 = 540 degrees
angle = 540 - 109 - 111 - 140 - 118 = 62
c. 4 sides, 2 triangles
2×180 = 360
angle = 360 - 60 - 142 - 100 = 58
d. 7 sides, 5 triangles
5×180 = 900
angle = 900 - 90 - 120 - 140 - 150 - 120 - 150 = 130
The given equations are
5x + 7y = 7
3x - 2y = 9
As a matrix equation,
A = [5 7
3 -2]
X = [x
y]
C = [7
9]
That is
a =5, c=7; and b=3, d=-2
a - b + c + d = 5 - 3 + 7 + (-2) = 7
Answer: 7
