For a start we will agree about designations. A leg call the party of a rectangular triangle which prilezhit to a right angle (i.e. makes a corner of 90 degrees with other party). Lengths of legs we will agree to designate an and b. Sizes of acute angles of a rectangular triangle, opposite to legs, we will call A and B respectively. A hypotenuse call the party of a rectangular triangle which protivolezhit to a right angle (i.e. is opposite to a right angle, with other parties of a triangle forms acute angles). We will designate length of a hypotenuse through page. We will designate Iskomaya Square through S.

## Instruction

1. Define what sizes of the considered rectangular triangle are known to you. Proceeding from it, choose proper expression.

2. Calculate the area of a rectangular triangle as a half of the work of legs, i.e. S=0.5*a*b in case their lengths are known to you.

3. Calculate the area by formula S = b*c*sin(A)/2 if to you one of legs (b), a hypotenuse (c), and also a corner (A) between them is set. This formula is fair not only for a rectangular triangle, but for any triangle in general.

4. Apply formula S = (a^2) / (2*tg (A)) in case to you only one of legs (a) is set, but also also opposite the corner (A) is known to this leg. He is familiar "" ^2"" operation of squaring is designated.

5. Use a formula S=(a^2) *tg (B)/2 d a case if to you only one of legs (a) is set, but also also adjacent the corner (B) is known to this leg.

6. Calculate to ploshchat on formula S = a*sqrt (c^2 – a^2)/2 if sizes of a leg (a) and a hypotenuse (c) are known to you. The operation sqrt is designated by a square root.

7. Use expression of S = (c^2) of *sin (A) *cos(A)/2 if the hypotenuse (c) and one of acute angles (A) is set.