In triangle ABC, the angle is C-straight, cosA = 0.6. Find tgB • cgtA

It is known triangle ABC.

Angle C is straight.

Since, cos A = 0.6, then sin b = 0.6.

1) cos ^ 2 a + sin ^ 2 a = 1;

0.6 ^ 2 + sin ^ 2 a = 1;

sin ^ 2 a = 1 – 0.6 ^ 2;

sin ^ 2 a = 1 – 0.36;

sin ^ 2 a = 0.64;

sin a = 0.8;

Hence, cos b = 0.8.

Let’s calculate:

tg B * ctg A = sin b / cos b * cos a / sin a = 0.6 / 0.8 * 0.6 / 0.8 = 0.36 / 0.64 = 0.18 / 0.32 = 0.09 / 0.16 = 9/16.

Answer: tg B * ctg A = 9/16.