Answer: The required measure of angle 3 is 60°.
Step-by-step explanation: We are given to find the measure of angle 3 from the figure if
m∠5 = 130° and m∠4 = 70°.
Let the measure of angle 3 be x°.
From the figure, we note that
angle 5 is an exterior angle and angles 3 and 4 are two remote interior angles of the triangle.
We know that
the measure of an exterior angle to a triangle is equal to the sum of the measures of two remote interior angles.
So, we get
[tex]m\angle 5=m\angle 3+m\angle 4\\\\\Rightarrow 130^\circ=x+70^\circ\\\\\Rightarrow x=130^\circ-70^\circ\\\\\Rightarrow x=60^\circ.[/tex]
Thus, the required measure of angle 3 is 60°.
