Problem on Finding Geometrical Figure's unknown Quantity

Topic : Geometrical Figure





Question : Find the area of triangle ABC where
angle ABC = 35 degrees
angle BCA = 110 degrees
angle CAB = 35 degrees
AND, length BC = 4 cm



ANSWER:





















Description Step1 : b = AC = BC because triangle ABC is isosceles
Triangle ABC are isosceles because angle ABC=angle BAC=35 degree



Description Step2 : sin 70 degrees = h/4
0.9369=h/4
h = 0.9369*4 = 3.759



Step3: Area = 0.5*b*h = 0.5*(4)(3.759) = 7.518 cm2