Answer:
Explanation:
note that all adjacent triangles will share an angle.
for 13 and 14 this is the case.
for 13 and 14 the adjacent sides are also multiples of each other proportionately. find this by dividing one side by the other for both triangles. if equal they are proportionately larger.
13 and 14 are both similar
for 15 and 16 the same logic can be applied to the side lengths. however, we are not given any information on the angles and cannot determine the angles mathematically.
for 17 and 18 the same logic can be applied again for the sides and given that the angles are confined within each other, the angles are the same.
for 17 and 18 you must add the side lengths for each side together and divide to determine the ratio and compare that to the ratio of the initial triangle