Question

Help please. Which set of numbers does not create a triangle?

900 cm, 60 cm, 0.5 m
12 m, 34 m, 40 m
145 ft, 14 yd, 105 ft
16 yd, 12 yd, 27 yd

Answer 1

I was thinking that the correct answer is the 2nd one but not sure

Answer 2

From each set of three length, ANY two must sum to more than the third. All three sets must work.

Example 3-4-5 is a triangle

3+4> 5
3+5> 4
4+5> 3

Answer 3

ok

Answer 4

Let's try #2

12 m, 34 m, 40 m

12 + 34 = 46 > 40
12 + 40 = 52 > 34
34 + 40 = 74 > 12

Looks like a triangle, to me.

Answer 5

ok I see how you did that

Answer 6

Careful on #1 and #3. The units are not consistent.

Note: It takes THREE successes to make a triangle. It takes only one failure to rule it out.

Answer 7

Ok yes I was looking at the units that are not the same

Answer 8

#3

145 ft, 14 yd, 105 ft

Forget that and work with this:

145 ft, 42 ft, 105 ft

Answer 9

145 + 42 = 187 > 105
145 + 105 = 250 > 42
42 + 105 = 147 > 145

Answer 10

So it would make a triangle correct?

Answer 11

Okay. Two more to try.

Answer 12

Ok so I just did the last one it makes a triangle too, so the answer it #1 that does NOT make a trirangle.

Answer 13

Prove it! 60 + 500 = 560 < 900. Done!!

Answer 14

I just worked it out too, thank you so much for explaining this to me and helping me.

Answer 15

Good work!