Posted by **Christopher** on Wednesday, January 5, 2011 at 8:26pm.

in a triangle DEF m<E is three times m<,and m <F is 9 less than m< E

- geometry -
**Henry**, Friday, January 7, 2011 at 7:05pm
D = X deg.

E = 3X,

F = 3X - 9.

X + 3X + (3X - 9) = 180deg.

7X = 180 + 9,

7X = 189,

X = 189 / 7 = 27deg.

D = X = 27deg.

E = 3X = 3*27 = 81deg.

F = 3X - 9 = 3*27 - 9 = 72deg.

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