Question

WILL MEDAL AND FAN.




Which statement about triangles is true?

A.
All acute triangles are also equilateral triangles.

B.
All right triangles are also isosceles triangles.

C.
All equilateral triangles are also acute triangles.

D.
Some obtuse triangles are also right triangles.

Answer 1

@mathstudent55

@Chelsealee

@superman36

Answer 2

Let's work through them.

Equilateral triangle: all sides (and angles) are equal
Acute triangle: all angles less than 90 degrees
Right triangle: 1 angle is exactly 90 degrees
Isosceles triangle: two equal sides (and angles)
Obtuse triangle: one angle greater than 90 degrees

Answer 3

http://www.regentsprep.org/regents/math/geometry/gp5/LTriangle.htm

Answer 4

that may help

Answer 5

Ok, thanks guys

Answer 6

My guess is that it's A.

Answer 7

Am I correct?

Answer 8

yes u r correct! :)

Answer 9

Ok, I posted this question cause I wasn't sure if it was C or A

Answer 10

lel

Answer 11

D

Answer 12

^an acute triangle

Answer 13

well, it is cute, too :-)

but as you have drawn it, it is actually obtuse, top angle slightly larger than 90 degrees

Answer 14

@ggcola
Did you find the correct answer?

Answer 15

Sorry I had to go somewhere to help my mom..so if A is wrong is it C? @mathstudent55

Answer 16

@ggcola I offered to work through them with you...

As mathstudent55 showed, it is possible to make an acute triangle which is not an equilateral triangle. That rules out A

We know that the sum of the interior angles of a triangle is 180 degrees, so it is not possible to have an obtuse triangle with a right angle, as those two angles alone would total more than 180 degrees. That rules out D

You can make a right triangle with angles 30, 60 and 90 degrees. That is proof that not all right triangles are isosceles triangles. That rules out B.

That leaves us with answer choice C: all equilateral triangles are also acute triangles. Well, if we have 3 equal angles and they total 180 degrees, each angle must be 1/3 of 180 degrees, or 60 degrees. 60 degrees is less than 90 degrees, so a triangle with 3 such angles is an acute triangle (all angles less than 90 degrees). Therefore, answer choice C is correct.