Can someone help me please.Watch
Show that AC=8.66cm correct to 3 significant figures.
The question tells you that they are equilateral triangles. There are some properties of such triangles that will allow you to fill in some angles here. Once you do this, it becomes a simply trigonometry problem.
1. Equilateral triangle, the sides of the triangle are the same 10 cm.
2. AC is a perpendicular bisector to the base and you get the length of BC (think about the proof).
3. Get AC through the Pythagorean theorem.
use the formula (number of sides-2) x 180
6-2 = 4
4 x 180 = 720
720 / 6 = 120
so 120 degrees is for one angle
the triangle's angles are half this so 120/2 = 60
I then used soh cah toa to work this out
so 10cm = hypotenuse and AC is the opposite
so sin(60) x 10 = 8.66
hope this helps. there are other ways to work this out but this is how i'd approach it.
helps to understand the basic trigonometry
- Study Helper