triangle upper T upper I upper C is an Isosceles triangle with a vertex angle I. If the measure of angle upper I equals 90 degrees, then find the measure of angle upper T.
Since triangle TIC is an isosceles triangle with a vertex angle I, this means that angles TIC and TCI are congruent. Since I equals 90 degrees, we can use the fact that the sum of the angles in a triangle is 180 degrees to find the measure of angle T.
The sum of the angles in triangle TIC is TIC + TCI + I = 180 degrees.
Since TIC and TCI are congruent, we can express this as 2T + I = 180 degrees.
Substituting I = 90 degrees, we get 2T + 90 degrees = 180 degrees.
Simplifying the equation, we get 2T = 90 degrees.
Finally, dividing both sides of the equation by 2, we find T = 45 degrees.
Therefore, the measure of angle T is 45 degrees.