Chapter 6.3, Problem 1WE

To determine

To write: an indirect proof of given conditional.

Answer to Problem 1WE

The correct first sentence would be: Assume that $m\angle B=40°$

Explanation of Solution

Given information:

If $m\angle A=50°,$ then $m\angle B=40°$

Calculation:

Consider the following statement:

If $m\angle A=50,$ then $m\angle B=40,$

If someone wants to write an indirect proof for this statement

There is need to write a correct first sentence of this indirect proof.

The correct first sentence would be: Assume that $m\angle B=40°$