Answer:
r = (ab)/(a+b)
Step-by-step explanation:
Consider the attached sketch. The diagram shows base b at the bottom and base a at the top. The height of the trapezoid must be twice the radius. The point where the slant side of the trapezoid is tangent to the inscribed circle divides that slant side into two parts: lengths (a-r) and (b-r). The sum of these lengths is the length of the slant side, which is the hypotenuse of a right triangle with one leg equal to 2r and the other leg equal to (b-a).
Using the Pythagorean theorem, we can write the relation ...
((a-r) +(b-r))^2 = (2r)^2 +(b -a)^2
a^2 +2ab +b^2 -4r(a+b) +4r^2 = 4r^2 +b^2 -2ab +a^2
-4r(a+b) = -4ab . . . . . . . . subtract common terms from both sides, also -2ab
r = ab/(a+b) . . . . . . . . . divide by the coefficient of r
The radius of the inscribed circle in a right trapezoid is r = ab/(a+b).
_____
The graph in the second attachment shows a trapezoid with the radius calculated as above.
Answer:
The answer is 15^3
Step-by-step explanation:
L*W*H
4*1 1/2*2 1/2
Answer:
The volume of the pyramid is 
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
step 1
Find the area of the base B

we have


substitute

step 2
Find the volume
we have


substitute


Pretty sure the answer is 77
Answer:
14.14 i hope this helps lol ;)