The ratio of the length and breadth of a rectangle is 5:4 and its area is 180 cm (i) Find its length and breadth (ii) Find its perimeter

Here is their argument. given the obtuse angle x, we make a quadrilateral abcd with ∠dab = x, and ∠abc = 90◦, and ad = bc. say the perpendicular bisector to dc meets the perpendicular bisector to ab at p. then pa = pb and pc = pd. so the triangles pad and pbc have equal sides and are congruent. thus ∠pad = ∠pbc. but pab is isosceles, hence ∠pab = ∠pba. subtracting, gives x = ∠pad−∠pab = ∠pbc −∠pba = 90◦. this is a preposterous conclusion – just where is the mistake in the "proof" and why does the argument break down there?

Rename mixed numbers before you can subtract are what

In the triangle abc< angle c is a right angle. find the value of the trig function indicated. find tan a if a =12, b=5 a. 13/12 b. 12/13 c. 5/12 d.12/5