10: an isosceles base angles are both equal. A triangle has 3 angles. All three angles added equals 180 in every triangle. since one of the base angle is 72 degrees then the other base angle is 72 degrees. ( a triangle has two base angles). so 72+72= 144
180-144= 36
The vertex angle = 36 degrees.
11: angles ratio is 2:4:6. Remember that all angles equal 180. Add the ratio amounts, 2+4+6= 12. Then divide 180 by 12 (180/12 = 15).
the smallest angle ratio is 2, so multiply 15 by 2 ( 15 * 2= 30 )
the smallest angle is 30 degrees.
12: all three angles of a triangle adds up to 180. thus, 64 + 74 + x = 180
138 + x = 180
x= 180 - 138
x = 42
x is the third angle. so the third angle is 42 degrees.
Answer:
B. False
Step-by-step explanation:
Given

Required
Is the distance between them 
Given that there are two points, the distance between them is calculated using
Distance = 
In this case;

Substitute these in the given formula
Distance = 
Comparing this with the given formula, both are not the same;
Hence, the formula is false and the correct formula is of the form 
Answer:
A rule of polygons is that the sum of the exterior angles always equals 360 degrees. Since it is a regular octagon, so each of the interior angles of octagon are equal. ((n-2)*180)/n where n is the number of sides of the polygon.for example in case n=8 for an octagon, so we get:
((8-2)*180)/8 => (6*180)/8 => 1080/8 = 135 degrees. This means that each interior angle of the regular octagon is equal to 135 degrees.
Each exterior angle is the supplementary angle to the interior angle at the vertex of the polygon, so in this case each exterior angle is equal to 45 degrees. (180 - 135 = 45). Remember that supplementary angles add up to 180 degrees.
And since there are 8 exterior angles, we multiply 45 degrees * 8 and we get 360 degrees.
This technique works for every polygon, as long as you are asked to take one exterior angle per vertex.
= 16 + 49 - 3(11) - 4(10)
= 16 + 49 - 33 - 40
= -8