Vi har

och . Om så . .Det är ett skönt problem. Tack så mycket, Kurre.

Yes that is the trigonometric approach

Good job!

Have you been studying swedish? I think I remember that you wrote that you are interested in languages. Nicely done!

Anyway here is my method:

Reflect AB in the horizontal line and draw line BC as in 2. Now reflect the triangle ABC in AC to make a quadrilateral as in 3. Now, all angles in the quadrilateral ABCD are equal, and all sides are equal, thus it is a square, and since AC is a diagonal,

must be half of a right angle, ie ]]>Vi har

och . Om så . .Det är ett skönt problem. Tack så mycket, Kurre.

]]>HOW TO READ THAT LANGUAGE??? can translate into english pls? thx

I did translate the important parts of the text:

Kurre wrote:

Find

Altough I should maybe have written that the figure consists of three squares, but that is kind of obvious.

]]>Find

This is an easy problem if you use the standard approach with trigonometry (the problem is for ~17 years old students). But I found a much nicer geometrical method, without using any trigonometry.

So my challenge for you is to find it.

(or solve it any other way without trigonometry is fine too )