Step-by-step explanation:
b is per the identity of angles on parallel lines when intersected by one inclined line the same as the 40° angle.
so,
b = 40°
due to the parallel nature of the 2 lines there is a symmetry effect for such shapes inscribed a circle. the upper and the lower triangle must be similar. and when applying a vertical line through the central crossing point, everything to the left is mirrored by everything on the right.
so, angle c must be equal to angle b.
c = 40°
and as the sum of all angles in a triangle is always 180°, d is then
d = 180 - 40 - 40 = 100°
the interior angle of the arc angle a is the supplementary angle of d (together they are 180°), because together with d they cover the full down side of the top-left to bottom-right line.
interior angle to a = 180 - 100 = 80°
due to the symmetry again, the arc angle opposite to a is the same as a.
as we know, the interior angle to a pair of opposing arc angles is the mean value of the 2 angles.
so, we have
(a + a)/2 = 80
2a/2 = 80
a = 80°
there might (and actually should) be some more direct approaches for "a" out of the other pieces of information, but that was the most straight one right out of my mind, and I don't spend time on finding additional shortcuts, when I have already a working approach.
Answer:B: 36°
Step-by-step explanation:
We know that ∆ABC is isoceles, making (angle)<ABC and <BCA congruent because base angles of isoceles triangles are congruent.
Because we have parallel lines, we can look for alternate interior angle pairs. <BCA is congruent to <DAC because they're alternate interior angles.
If <BCA is x then so is <ABC.
Since triangles add up to 180° we can add all of the angles (3x+x+x) and set it equal to 180.
3x+x+x=180
5x=180
x=36
If we were looking for <BAC we would plug that back in and solve, but we're looking for <BCA which is equal to x, therefore m<BCA=36°
The answer would be 16.
8+8=16
Answer:
r=3
Step-by-step explanation:
3(r - 7) = 4(2 - 2r) + 4
Distribute
3r -21 = 8 -8r +4
Combine like terms
3r -21 = 12 -8r
Add 8r to each side
3r +8r-21 = 12 -8r+8r
11r -21 = 12
Add 21 to each side
11r -21+21 =12+21
11r = 33
Divide each side by 11
11r/11 = 33/11
r = 3
Answer/Step-by-step Explanation:
True. Expressions cm be expressed using the above listed
