Question

If ABC=DEF and m <E= 2(m-15)° find m​

Answer 1

Answer:  m = 25

====================================================

Work Shown:

Triangle ABC is congruent to triangle DEF. The order of the lettering is important because it tells us how the angles pair up. We see that angle B and angle E are the second letters of ABC and DEF respectively. Because the triangles are congruent, this leads to angle B = angle E.

Angle B is shown to be 20 degrees, so,

angle E = angle B

2(m-15) = 20

m-15 = 20/2

m-15 = 10

m = 10+15

m = 25

------------------

A slightly alternative way to solve:

2(m-15) = 20

2m-30 = 20

2m = 20+30

2m = 50

m = 50/2

m = 25

------------------

Checking the answer:

2(m-15) = 20

2(25-15) = 20

2(10) = 20

20 = 20

We get the same thing on both sides, so we end up with a true equation. This means the first equation is true when m = 25. The solution has been confirmed.