The surface area is 870 cm².
Since the base is a regular quadrilateral, each side is the same; dividing the perimeter by 4 will give us the side length:
60/4 = 15
To find the area, we square the side length:
15² = 225
There are two bases, so the area of these is 2(225) = 450
There are 4 lateral faces, so the lateral area is 4(105) = 420
Together, this gives us a total surface area of 870.
Answer:
85°
Step-by-step explanation: Hope it helps!
The greatest common factor is 2
First line because 4(2a+1)=8a+4 and 9a+4-(8a+4)= a
Second line because a times 2 =2a and 2a+1-2a=1
<span>Although the second equality is more or less obvious since 2a+1 leaves a remainder of 1 when divided by a.</span>
The lower square root would be 4.2
