Question

Another question. Help is very much appreciated!

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(See attachment)

Answer 1

According to the triangle inequality theory the sum of 2 sides of a triangle need to be grater than the 3rd side.

If we sum 7 + 12 we obtain a result of 19. Since nineteen is the answer, we select all the options that summed with either 12 or 7 are lower than 19 but greater than 5 (because if you sum up 5 with the numbers, the answers won't match according to the theory):

A, B, C & D

Hope it helped,

Happy homework/ study/ exam!

Answer 2

The triangle inequality says the two smallest sides have to add up to strictly more than the biggest. So when 7 and 12 are the smaller sides the biggest can't be 19 or larger. When 12 is the largest side the smallest side can't be 5 or smaller. So we check those in the open interval (5,19):

Answer: A B C D