AD is perpendicular to BC and d,

Perpendicular to AC and e.

therefore

Triangle ABD and triangle ABE

This is a right triangle.

because

M is the midpoint of AB.

therefore

MD=AB/2

ME=AB/2

therefore

MD = me,

Triangle Mediterranean is an isosceles triangle.

(2)

because

AD is perpendicular to BC and D.

,

Perpendicular to AC and e.

therefore

One,

b，

d，

E

Four dots * * * circle

therefore

Angle EDC= angle back.

because

AD is perpendicular to BC and d,

M is the midpoint of AB,

therefore

MD=MB，

therefore

Angle MDB= angle ABC.

because

Angle EDC+ Angle MDE+ Angle MDB= Angle BAC+ Angle ACB+ Angle ABC= 180 degrees.

therefore

Angle MDE= angle ACB

because

Triangle Mediterranean is an isosceles triangle.

therefore

Angle EMD= 180-2 Angle MDE= 180-2 Angle ACB.

because

AD is perpendicular to BC and D.

therefore

Angle ACB=90 degree angle DAC

therefore

Angle EMD= 180 degrees -2 (90 degrees-angle DAC)

= dual angle DAC