Answer: 
Step-by-step explanation:
Using the Pythagorean theorem,

Answer:
option C. 
Step-by-step explanation:
we know that
The volume of the triangular pyramid is equal to

where
B is the area of the triangular base
h is the height of the pyramid
In this problem we have


substitute in the formula

The question given above may be answered through the concept of ratio and proportion. The ratio of the man's weight on Earth and Mars should be equal to the ratio of the rock's weight on Earth and Mars. By letting x be the rock's mas on Earth, the equation that would best represent the situation is,
180 / 72 = x / 16
The value of x is equal to 40. Thus, the rock weighs 40 pounds on Earth.
81 is 45% of 180.
Simply multiply the percentage rate to the whole to get the part it is representing.
180 is the whole or 100%
45% is the percentage rate of the part.
180 x 45% = 81
81 is the value of the part
Assuming the part and the whole is given, to get the percentage rate, simply divide the part by the whole. and multiply its quotient by 100%.
81/180 = 0.45 x 100% = 45%
In the instance that the part and its corresponding percentage rate is given, find the whole. divide the part by its percentage rate.
81/45% or 81/0.45 = 180