A: hexagon
B: pentagon
C: square
D: triangle
What polygon's interior angles add up to 180 degrees?
2015-12-10 6:39 pm
回答 (18)
2015-12-20 7:22 am
The way you figure this out is actually very interesting.
You measure the OUTSIDE angles, and the outside angles from each vertex always add up to 360 degrees since going around makes 1 complete rotation.!!!
Outside angles of triangles is 360/3 = 120
inside angles are then 180-120 = 60
60 x 3 = 180 degrees. <<<answer D is correct.<<<<
Outside angles of a rectangle/square is 360/4 = 90
180-90 = 90
90 x 4 = 360 degrees sum of interior angles.
pentagon: 360/5 = 72
180-72 = 108
108 8 5 = 540 degrees
etc
You measure the OUTSIDE angles, and the outside angles from each vertex always add up to 360 degrees since going around makes 1 complete rotation.!!!
Outside angles of triangles is 360/3 = 120
inside angles are then 180-120 = 60
60 x 3 = 180 degrees. <<<answer D is correct.<<<<
Outside angles of a rectangle/square is 360/4 = 90
180-90 = 90
90 x 4 = 360 degrees sum of interior angles.
pentagon: 360/5 = 72
180-72 = 108
108 8 5 = 540 degrees
etc
2015-12-11 7:45 am
Triangle from elementary geometry.
The long way. The sum of the interior angles of an n-sided polygon is 180°(n - 2)
180°(n - 2) = 180°
n - 2 = 1
n = 3
The long way. The sum of the interior angles of an n-sided polygon is 180°(n - 2)
180°(n - 2) = 180°
n - 2 = 1
n = 3
2015-12-23 12:30 am
n[pi - 2pi/n] = pi, ie., n[1 - 2/n] = 1, ie., n-2 = 1, ie., n = 3. Answer is D:, a triangle.
2015-12-22 12:57 pm
For a polygon with n sides , the sum of the interior angles is 180(n-2)
180(n-2) = 180
180n-360 = 180
180n = 540
n = 3
3 sides polygon (a triangle)
180(n-2) = 180
180n-360 = 180
180n = 540
n = 3
3 sides polygon (a triangle)
2015-12-20 7:41 am
all of them
2015-12-20 3:20 am
D. triangle
2015-12-19 10:17 am
D_____Triangle
2015-12-18 7:29 pm
triangle
2015-12-18 3:36 am
D: triangle
2015-12-17 7:44 am
Its D .Triangle
2015-12-16 3:44 pm
Ans. triangle D
2015-12-16 4:44 am
D
2015-12-14 12:11 pm
D triangle
2015-12-14 10:05 am
D
2015-12-13 11:49 am
D
2015-12-12 4:31 pm
Answer 'D' a triangle.
For information the interior angles of ; sum to
Square 360
Pentagon = 540
Hexagon = 720.
NB for each additional side add '180' .
For information the interior angles of ; sum to
Square 360
Pentagon = 540
Hexagon = 720.
NB for each additional side add '180' .
2015-12-11 12:20 pm
D
2015-12-10 6:47 pm
D: Triangle
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