Triangle ABC is an isosceles triangle with line AB=lineAC...??? please help, i will leave u good points!!?

Question

Triangle ABC is an isosceles triangle with line AB=lineAC . The measure of angle A is 40 degrees. Find the measure of the angle opposite line AB . Please show how to solve this and your answer, thanks!! i will leave good points!


40
60
140
70

Answer 1

[Note: < denotes angle]

(Because, in a triangle, sum of the angles is 180)


Because this is an isosceles triangle, AB = AC, the angles opposite the equal sides are equal (congruent),
therefore
Substituting value of

2 *

Answer 2

Since the sum of the degrees in a triangle equals 180 degrees and you have A at 40 degrees. That leaves 140 degrees between B and C. Since this is an isosceles triangle, both B and C are the same angle so divide 140 by 2 leaves you with 70 degrees.

70 degrees. Final answer. :)

Answer 3

I don't want to think too much so I'll figure this way:

An isoceles has 2 equal angles, and all three add to 180. Since you've told me that one of the angles is 40, then I know that it doesn't have 3 angles of 60 but rather 1 angle of 40 and 2 angles of (180-40)/2 = 70 each. Ta Da.

An equalateral triangle is a special case of the isoceles. It has the required 2 equal angles and also a third angle that also the same, hence all three angles are 60.

Answer 4

Angle A = 40
Angle B = Angle C (In an isosceles triangle, the angles opposite the equal sides are equal)
Angle B + Angle C can be written as 2(Angle C)
In a triangle, sum of the angles is 180.
Angle A + Angle B + Angle C = 180
Angle A + 2(Angle C) = 180
2(Angle C) + 40 = 180
2(Angle C) = 180-40 = 140
Angle C = 140/2 = 70
The angle opposite AB is equal to 70 degrees

Answer 5

Given triangle ABC Side AB = AC, Angle A =40
Since it is isosceles the 2 angles opposite the two identical sides are equal
All triangle are 180 deg
therefore A+B+C=180 deg
40+B+C = 180
C+B =140
but since B=C
C+C = 140
2C=140
C=70

Answer 6

angle CAB is 40°
and you know angles ACB and CBA are equal because if the sides of triangle are congruent, their corresponding angles also are congruent. Also you know that there are 180° in a triangle

so set up an equation
180 = 40 + 2x
140 = 2x
x = 70°

Answer 7

in any triangle the sum of the 3 angle is 180 degrees so if one angle ( the vertex angle ) ( as in your example angle A ) is equal to 40 degrees the base angles are equal in mesurement so all you have to do is subtract the mesurement of the vertex angle from the total mesurement of the triangle
therefore

180 - 40 = 140 and since the two base angles are equal 140 / 2 = 70 degrees Thanks for the points

Answer 8

6=AC=BC=2x+2 6=2x+2 divide by 2 3=x+1 subtract 1 x=2 AB=x+1=3

Answer 9

Angle A = 40°
Angles B and C are congruent.
The sum of all three is 180° (as it is for all triangles).

Do the math...

Answer 10

AB=AC
so angleB=angleC
let B & C each be x
then
x+x+40=180
2x+40=180
2x=140
x=70