In ΔABC, mÐA= 40, mÐB= 70, andAC= 5 centimeters. Find the

length ofABin centimeters.

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- Oct 14th 2008, 09:01 PMmagentaritaFind Length AB
In Δ

*ABC*, mÐ*A*= 40, mÐ*B*= 70, and*AC*= 5 centimeters. Find the

length of*AB*in centimeters. - Oct 15th 2008, 10:11 AMmasters
Since $\displaystyle m\angle A=40^{\circ}, m \angle B=70^{\circ}$, it follows that $\displaystyle m\angle C=70^{\circ}$ since the sum of the measures of the angles of a triangle is 180 degrees.

If two angles of a triangle are congruent, then the triangle is isosceles.

If the triangle is isosceles then the sides opposite the congruent angles are congruent.

$\displaystyle \angle B \cong \angle C \rightarrow \overline{AC} \cong \overline{AB}$

$\displaystyle AC = AB = 5$cm.