What's bigger 20 or -25

Tracy solved the following problem. which of the statements is true? 9 ÷ 3 + 6 × 2 3 + 6 × 2 9 × 2 18 her answer is correct. her answer is incorrect. she should have multiplied before dividing. her answer is incorrect. she should have multiplied before adding. her answer is incorrect. she should have added before dividing.

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

Aadc is formed by reflecting aabc across line segment ac, as shown in the figure. if the length of ac is 4 units, the area of aadc is square units.