Read the following statements. The sum of the angle measures of a triangle is 180°. Two angles of a triangle measure 40°and 60", so Juan concludes that the third angle measures 80°. What do you notice about the how the conclusions were made from
the statement above?

what number must be added to sum of two angles that the sum of three angles become 180.

Since sum of two angles is 100 , 80 must be added to 100 to make it equal to 180.

Step-by-step explanation:

Given

sum of measure of angle of triangle = 180°

given two angles 40°and  60°

Let the third angle be x°

thus

40°+  60°+x° = 180°

100°+x° = 180°

x° =  180°- 100° =  80°

Thus, third angle measure 80°

She must have sum the first two known angles.

as given sum of three angles are 180

she must have assumed other angle to be x

then sum of all three angles must be 180

now to find third angle she subtracted sum of two known angles to find third angle.

other way can what number must be added to sum of two angles that the sum of three angles become 180.

Since sum of two angles is 100 , 80 must be added to 100 to make it equal to 180.