Trigonometry, right triangles?

Question

Solve each of the following right triangles. In each case, C = 90 deg. If the angle info is given in deg and min, give the answers in the same way. If given in decimal deg, do likewise in your answers. When two sides are given, give answers in degrees and minutes.

A = 61 deg 00'; b = 39.2cm

Could someone explain this a little to me? I'm a little confused on where to start. (Of course angle B is 29 deg 00'.)

Answer 1

1} Angle B is 90-61 = 29 deg.

2} You have the side OPPOSITE angle B, and you want to

find the HYPOTENUSE, AB. Opposite and hypotenuse

are connected by the sine ratio, so:

sin29 = 39.2/AB, so,

AB sin29 = 39.2, so

AB = 39.2/sin29. You can calculate that !

3} You now need to calculate BC, and using a similar method

tan 29 = 39.2/BC.....................

Just a couple of points: try not to use something that you have already calculated to work out a subsequent part of the question. If you have got the first part incorrect, then your subsequent working will be wrong. Always try to use the information given in the question instead. Hope this helps, Twiggy.

Answer 2

You have B and b, so you can work out c (sin B = b/c, so c = b / sin B). Then you can get a = √(c^2 - b^2).