Answer:
he did not perform enough trials
Step-by-step explanation:
The base angles of an isosceles triangle are equal
The base angles are 15 degrees, while the vertex angle is 150 degrees
The base angles are given as:
Base = (6a- 3) and (a + 12)
So, we have:
![\mathbf{6a -3 =a + 12}](https://tex.z-dn.net/?f=%5Cmathbf%7B6a%20-3%20%3Da%20%2B%2012%7D)
Collect like terms
![\mathbf{6a -a =3 + 12}](https://tex.z-dn.net/?f=%5Cmathbf%7B6a%20-a%20%3D3%20%2B%2012%7D)
![\mathbf{5a = 15}](https://tex.z-dn.net/?f=%5Cmathbf%7B5a%20%3D%2015%7D)
Divide both sides by 5
![\mathbf{a = 3}](https://tex.z-dn.net/?f=%5Cmathbf%7Ba%20%3D%203%7D)
Substitute 3 for a in Base = (6a- 3),
![\mathbf{Base = 6 \times 3 - 3}](https://tex.z-dn.net/?f=%5Cmathbf%7BBase%20%3D%206%20%5Ctimes%203%20-%203%7D)
![\mathbf{Base = 18 - 3}\\](https://tex.z-dn.net/?f=%5Cmathbf%7BBase%20%3D%2018%20-%203%7D%5C%5C)
![\mathbf{Base = 15}](https://tex.z-dn.net/?f=%5Cmathbf%7BBase%20%3D%2015%7D)
So, the base angle is 15 degrees.
The vertex angle is calculated using:
![\mathbf{Vertex=180 -2 \times Base}](https://tex.z-dn.net/?f=%5Cmathbf%7BVertex%3D180%20-2%20%5Ctimes%20Base%7D)
So, we have:
![\mathbf{Vertex=180 -2 \times 15}](https://tex.z-dn.net/?f=%5Cmathbf%7BVertex%3D180%20-2%20%5Ctimes%2015%7D)
![\mathbf{Vertex=150 }](https://tex.z-dn.net/?f=%5Cmathbf%7BVertex%3D150%20%7D)
Hence, the vertex angle is 150 degrees
Read more about isosceles triangles at:
brainly.com/question/25739654
Explanation:
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∠TAB = x°
∠TAC = 90°
(Angle between tangent and radius)
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∠CAB = a = 90 - x
∠CBA = 90°
(Angle in a semi circle)
∠ACB = 180 - 90 - a (3ʳᵈ angle of triangle)
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In geometry, the three undefined terms are: the point, the plane and the straight line.
Since all the given graphs represent lines,we will need to choose the straight line among them.
Straight line is a line that has no start and no end.
From the choices:
Figures a and c are rays
figure b is a line segment
figure d is a straight line
Therefore, the correct choice is: D