SOLUTION: △ABC with m∠A = m∠B = 45° and BC = 4 Find: AB approximation

Algebra ->  Formulas -> SOLUTION: △ABC with m∠A = m∠B = 45° and BC = 4 Find: AB approximation       Log On


   

Question 1206650: △ABC with m∠A = m∠B = 45° and
BC = 4
Find: AB approximation
Answer by ikleyn(52788) About Me  (Show Source):
You can put this solution on YOUR website!
.

This triangle has two base angle congruent, A and B, so, the triangle is isosceles.


Two angles are 45° each - hence, the third angle, C,  is  180° - 45° - 45° = 90°.


Thus the triangle is a right-angled isosceles triangle with lateral sides AC and BC.


Since AC = BC = 4 cm,  we have then  AB = sqrt%284%5E2%2B4%5E2%29 = 4%2Asqrt%282%29  (Pythagoras).


ANSWER.  AB = 4%2Asqrt%282%29 = 5.656854249  (approximately).

Solved.