DC is the hypotenuse of a right triangle, so that's easy.
tan ∠ADC = 5/3
use the law of cosines to find ∠ACB
If you know two sides A and B of a triangle, and the angle θ between them, then the area of the triangle is 1/2 AB sinθ
The area of ABCD is the sum of triangles ABD and ADC
In the figure AB = 11cm, BC = 8cm, AD = 3cm, AC = 5cm and DAC is a right angle.
(a) length DC;
(b) the size of ADC;
(c) the size of ACB;
(d) the area of the quadrilateral ABCD.
1 answer
3 answers