<u>Answer:
</u>
The volume of pyramid with dimensions 4cm , 4cm by 12cm is 
<u>Solution:
</u>
Volume of a pyramid can be found out by using the below formula,

where,
v is the volume of pyramid
l is the length of pyramid
w is the width of pyramid
h is the height of pyramid
from question, given that l = 4 ; w = 4; h = 12
hence the volume of pyramid for the given dimensions is


So the volume of pyramid is 
The remaining area that the grass will cover will be given by:
Area=[area of rectangle]-[area of the triangle]
area of rectangle will be:
A1=length*width
=20*8
=160 square feet
The area of the triangle will be:
A2=1/2absin theta
since the triangle is equilateral, all the angles are equal and the size of each angle is 60°. Thus the area will be:
A2=1/2*5*5sin 60
=18.3
thus the remaining area of the grass will be:
Area=160-18.3
=149.7 square feet
Answer:
Let us assume the total number of students surveyed = x
Then
Number of students preferring red = x/4
Number of students preferring blue = x/8
Then
Number of students remaining = x - [(x/4) + (x/8)]
=x - [(2x + x)/8)
= x - (3x/8)
= (8x - 3x)/8
= 5x/8
Number of students preferring the color green = (3/5) * (5x/8)
= 3x/8
We also know that the total number of students preferring the color green is 15
So
3x/8 = 15
3x = 15 * 8
x = (15 * 8)/3
= 5 * 8
= 40
So in total 40 students were surveyed. I hope the procedure is clear to you.
Step-by-step explanation: