SOLUTION: Please tell me where we went wrong. The answer does not check out when you put it back into the equation. I know what the right answer is from trial and error, but I can't get th

Question 451004: Please tell me where we went wrong. The answer does not check out when you put it back into the equation. I know what the right answer is from trial and error, but I can't get the equation to get the right answer for me. WHAT AM I DOING WRONG? HELP!
The problem is: what is the height of a triangle if the base= 1/2h and the area = 196 mmsquared?
height = h
base = 1/2 h
A= 196 mm squared
so
A=1/2bh
A=1/2(1/2h)(h)
196=1/2(1/2h)(h) can't we multiply both sides by 2 to get...?
392=(cancels)(cancels h)(2h) or
392=2h*h
392=2h squared (divide both sides by 2)
196=h squared (take the square root of h and 196)
14=h
So height = 14 and base= 1/2h=1/2(14)/7.
Check answer:
196 = 1/2 (7) (14)
196 = 1/2 * 98
196 does not = 49

Answer by edjones(8007) (Show Source): You can put this solution on YOUR website!
b=.5h, A=196 mm^2
.5bh=A
.5*.5h*h=196
.25h^2=196
h^2=784
h=28 mm
.
Ed
.
PS:
196=1/2(1/2h)(h) can't we multiply both sides by 2 to get...?
NO we can't! You can cancel off one 1/2 only when multiplying or dividing. Also (1/2h) is incorrect. (h/2) is correct and easiest. Also h(1/2) is correct.
.
I'm glad to help someone who shows their work like you have.
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