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## Comment on

ABC Perimeter## Isn't it impossible for the

## There's nothing in the

There's nothing in the question that states ABC is a right triangle? So, there isn't a hypotenuse to speak of.

Are you confusing "isosceles triangle" with "right triangle"?

## Sir how can the unknown

if length is 4 then the angles on the opposite sides wont match.

In this way we can changed any figure in any way and the answer will yield D, and by the looks of it, 4 is the longest side and 3 is the shortest length on both sides.

## "...by the looks of it, 4 is

"...by the looks of it, 4 is the longest side and 3 is the shortest length on both sides"

The diagrams in Quantitative Comparison questions are not necessarily drawn to scale. So, in this question, we can't make assumptions about which two sides are equal.

For more on what assumptions we can and cannot make, watch: https://www.greenlighttestprep.com/module/gre-geometry/video/863

## Hello! I was confused because

|A-B| < 3rd side < A+B

I guess for Isosceles, above method is not qualified? This only works on right triangle??

## The rule, |A-B| < 3rd side <

The rule, |A-B| < 3rd side < A+B, applies to ALL triangles.

So, for this question, we know that: |4-3| < 3rd side < 4+3

However, in the given question, we're also told that the triangle is isosceles.

So, the 3rd side must have length 3 or 4 (to match one of the given sides)

Cheers,

Brent

## Understood perfectly! Thank

## Are we going to be told which

## Unfortunately no. We won't be

Unfortunately no. We won't be told which diagrams are drawn to scale and which aren't. So, we must assume that all diagrams are NOT drawn to scale.

For more on what can and cannot be assumed, watch https://www.greenlighttestprep.com/module/gre-geometry/video/863

Cheers,

Brent

## Hi Brent

In the video at 00:51 you have calculated the permiter when BC=3 then 3+3+4=13 should be there

BC=4 then 4+4+3=11

Am I calculating the perimeter in a wrong way

Thanks

## When BC = 3, then the three

When BC = 3, then the three lengths are 3, 3 and 4.

You're correct to say that the perimeter = 3 + 3 + 4

However, 3 + 3 + 4 = 10 (not 13)

Cheers, Brent

## Hi Brent if BC is 4, the will

The grater angle has longest sides A<B<C a<b<c

## Sorry Vineet. I'm not sure

Sorry Vineet. I'm not sure what you're asking. Can you rephrase your question?

## Sorry Vineet. I'm not sure

Sorry Vineet. I'm not sure what you're asking. Can you rephrase your question?

## Hello Brent we have a rule

## If BC = 3, then the three

If BC = 3, then the three lengths are 3, 3 and 4, which means AC is the longest side, which means angle B is the biggest angle.

If BC = 4, then the three lengths are 3, 4 and 4, which means AC and BC are tied for the longest side, which means angle A and angle B are tied for the biggest angle.

Having said all of that, the relationship between angles and lengths doesn't really apply here. All we need to know is that an isosceles triangle has two equal sides, since this is all we need to calculate the perimeter.

Does that help?

## Since we have sides measure

## There are infinitely many

There are infinitely many triangles that have sides with lengths 3 and 4.

IF the angle between those two sides is 90°, then the third side will have length 5.

Otherwise all we can say is: 1 < length of 3rd side < 7 (after applying the property described here https://www.greenlighttestprep.com/module/gre-geometry/video/860)

## Oh, I see. So, it needs to be