NO ONE EVER HELPS ME , PLEASE HELP ME I NEED HELP! If A=1/2 h (b1 +b2) is the formula for the area of a trapezoid, find the height of the trapezoid that has an area of 78 in ^2 and base lengths 5 in and 8 in.

A is the answer  

12 in

first substitute the variables

then 78=1/2h(5 + 8)

this makes it an equation

add similar terms which equals to

78=1/2xhx13

then divide both sides by 13

6=1/2xh

lastly divide both sides by 1/2

12=h

Step-by-step explanation:

proof

A=1/2x12(5 + 8) then

A=1/2x12x13  then

   A=6x13  then

       A= 78in^2

answer: the answer is (b) amie should have multiplied

step-by-step explanation: given a sphere and a cylinder with same radius and height.

let, 'r' be the radius of the cylinder and sphere and 'h' be the height of the cylinder. according to the question,

r = h.

now, the volume of the sphere will be

and the volume of the cylinder will be

therefore, we have

thus, ammie should have multiplied the volume of the sphere

the equation cos(35) =a/25 can be used to find the length of bc what is the length of bc? round to the nearest tenth

step-by-step explanation: