Hello can you help om really struggling ​

What effect would doubling all the dimensions of a triangular pyramid have on the volume of the pyramid? explain your reasoning.

What is the similarity ratio of a cube with volume 729m^3 to a cube with volume 3375 m^3

Which of these side lengths could form a triangle a) 2 cm , 2 cm , 4 cm b) 3 cm , 5 cm , 10 cm c) 3 cm , 4 cm , 5 cm d) 4 cm , 8 cm , 15 cm