Question has missing figure, the figure is in the attachment.
Answer:
The measure of ∠1 is 65°.
The measure of ∠2 is 65°.
The measure of ∠3 is 50°.
The measure of ∠4 is 115°.
The measure of ∠5 is 65°.
Step-by-step explanation:
Given,
We have an isosceles triangle which we can named it as ΔABC.
In which Length of AB is equal to length of BC.
And also m∠B is equal to m∠C.
ext.m∠C= 115°(Here ext. stands for exterior)
We have to find the measure of angles angles 1 through 5.
Solution,
For ∠1.
∠1 and ext.∠C makes straight angle, and we know that the measure of straight angle is 180°.
So, we can frame this in equation form as;
![\angle1+ext.\angle C=180\°](https://tex.z-dn.net/?f=%5Cangle1%2Bext.%5Cangle%20C%3D180%5C%C2%B0)
On putting the values, we get;
-115\°=65\°[/tex]
Thus the measure of ∠1 is 65°.
For ∠2.
Since the given triangle is an isosceles triangle.
So, ![m\angle1=m\angle2](https://tex.z-dn.net/?f=m%5Cangle1%3Dm%5Cangle2)
Thus the measure of ∠2 is 65°.
For ∠3.
Here ∠1, ∠2 and ∠3 are the three angles of the triangle.
So we use the angle sum property of triangle, which states that;
"The sum of all the angles of a triangle is equal to 180°".
![\therefore \angle1+\angle2+\angle3=180\°](https://tex.z-dn.net/?f=%5Ctherefore%20%5Cangle1%2B%5Cangle2%2B%5Cangle3%3D180%5C%C2%B0)
Now we put the values and get;
![65\°+65\°+\angle3=180\°\\\\130\°+\angle3=180\°\\\\\angle3=180\°-130\°=50\°](https://tex.z-dn.net/?f=65%5C%C2%B0%2B65%5C%C2%B0%2B%5Cangle3%3D180%5C%C2%B0%5C%5C%5C%5C130%5C%C2%B0%2B%5Cangle3%3D180%5C%C2%B0%5C%5C%5C%5C%5Cangle3%3D180%5C%C2%B0-130%5C%C2%B0%3D50%5C%C2%B0)
Thus the measure of ∠3 is 50°.
For ∠4.
∠4 and ∠2 makes straight angle, and we know that the measure of straight angle is 180°.
So, we can frame this in equation form as;
![\angle2 +\angle 4 =180\°](https://tex.z-dn.net/?f=%5Cangle2%20%2B%5Cangle%204%20%3D180%5C%C2%B0)
Substituting the values of of angle 2 to find angle 4 we get;
![65\°+ \angle 4 = 180\°\\\\ \angle 4 = 180\°-65\°\\\\\angle 4= 115\°](https://tex.z-dn.net/?f=65%5C%C2%B0%2B%20%5Cangle%204%20%3D%20180%5C%C2%B0%5C%5C%5C%5C%20%5Cangle%204%20%3D%20180%5C%C2%B0-65%5C%C2%B0%5C%5C%5C%5C%5Cangle%204%3D%20115%5C%C2%B0)
Thus the measure of ∠4 is 115°.
For ∠5.
∠4 and ∠5 makes straight angle, and we know that the measure of straight angle is 180°.
So, we can frame this in equation form as;
![\angle4 +\angle 5 =180\°](https://tex.z-dn.net/?f=%5Cangle4%20%2B%5Cangle%205%20%3D180%5C%C2%B0)
Substituting the values of of angle 4 to find angle 5 we get;
![115\°+ \angle 5 = 180\°\\\\ \angle 5 = 180\°-115\°\\\\\angle 5= 65\°](https://tex.z-dn.net/?f=115%5C%C2%B0%2B%20%5Cangle%205%20%3D%20180%5C%C2%B0%5C%5C%5C%5C%20%5Cangle%205%20%3D%20180%5C%C2%B0-115%5C%C2%B0%5C%5C%5C%5C%5Cangle%205%3D%2065%5C%C2%B0)
Thus the measure of ∠5 is 65°.
Hence:
The measure of ∠1 is 65°.
The measure of ∠2 is 65°.
The measure of ∠3 is 50°.
The measure of ∠4 is 115°.
The measure of ∠5 is 65°.