If the measures of the angles in a triangle are in the ration 3:4:5, the measure of the exterior angle of the triangle can not be

a) 120D b)165D c)105D d)135D

b 165

With the triangle ratio of 3:4:5 the equation can be made:
3x + 4x + 5x = 180
x = 15
The angels of the triangle then are 45, 60, and 75.
Their exterior angles are:
135, 120 and 105
Thus choice b is not a correct responce.

To find the solution to this question, we need to understand the concept of exterior angles of a triangle.

In any triangle, the sum of the three exterior angles is always 360 degrees.

Given that the measures of the angles in the triangle are in the ratio 3:4:5, let's assume the angles are 3x, 4x, and 5x, where x is a constant.

To find the value of x, we can set up the equation:

3x + 4x + 5x = 180
12x = 180
x = 180/12
x = 15

Now that we know the value of x, we can find the measures of the angles:
3x = 3 * 15 = 45
4x = 4 * 15 = 60
5x = 5 * 15 = 75

The measures of the angles in the triangle are 45, 60, and 75 degrees.

To find the exterior angles, we simply subtract the interior angle from 180 degrees:
Exterior angle of 45 degrees = 180 - 45 = 135 degrees
Exterior angle of 60 degrees = 180 - 60 = 120 degrees
Exterior angle of 75 degrees = 180 - 75 = 105 degrees

Now we can check the options given:
A) 120 degrees: This is a valid exterior angle.
B) 165 degrees: This is not a valid exterior angle based on the given measures.
C) 105 degrees: This is a valid exterior angle.
D) 135 degrees: This is a valid exterior angle.

Therefore, the measure of the exterior angle that cannot be in this triangle is option B) 165 degrees.