Discussion
In the figure above, triangle ABC is isosceles with base AC. If x = 60°, then AC =
| (A) | 2 |
| (B) | ... |
| (C) | ... |
| (D) | ... |
| (E) | ... |
| (F) | ... |
The solution is
Posted: 12/29/2011 17:00
Need further explanation thank u
Posted: 12/30/2011 08:30
The basic deal is that the isosceles triangle turns out to be an equilateral triangle:
The sum of all angles in any triangle is 180, since 180 minus 60 is 120 and the fact given it to be an isosceles triangle -> has 2 equal sides(length) AND 2 equal angles.
So, the remaining two angles should be equal -> 120/2=60 OR we have one of 60 plus one other (isosceles property) give also 180-120=60.
Either give us the information, this triangle has 3 equal angles and is thus equilateral and has the equilateral property of 3 equal sides -> know 1, know all ;)
Niels
Greetings from Holland
Ps.
You could even solve it with regular Phytagoras split the 60 into two right angled triangles. (30+90+60=180) use soh, cah, toa(*)
(*) I hope the translation is correct, in Holland it's sos, cas, toa.
The sum of all angles in any triangle is 180, since 180 minus 60 is 120 and the fact given it to be an isosceles triangle -> has 2 equal sides(length) AND 2 equal angles.
So, the remaining two angles should be equal -> 120/2=60 OR we have one of 60 plus one other (isosceles property) give also 180-120=60.
Either give us the information, this triangle has 3 equal angles and is thus equilateral and has the equilateral property of 3 equal sides -> know 1, know all ;)
Niels
Greetings from Holland
Ps.
You could even solve it with regular Phytagoras split the 60 into two right angled triangles. (30+90+60=180) use soh, cah, toa(*)
(*) I hope the translation is correct, in Holland it's sos, cas, toa.
Posted: 12/05/2012 11:36
I think you're right. Shouldn't the answer be (C) from this point of view?