If A = 1/2h (b+c), what is the value of b???
A= 50
h= 4
c= 11
the answer choices are:
(1) 14
(2) 24
(3) 36
(4) 56
I already know the answer is 14. but when i do the math, i can't seem to get that value! can someone please help me do this problem? i don't want just the answer, i want you to show the work too! please help! thank you so much!!!
2007-12-31 18:56:35 · 7 answers · asked by ivory_plr 4 in Science & Mathematics ➔ Mathematics
A=1/2*h(b+c)
50=1/2*4(b+11)
50=2(b+11)
since half of 4=2;
50=2b+22
50-22=2b
28=2b
28/2=b
b=14
2007-12-31 19:06:17 · answer #1 · answered by vkv 2 · 1⤊ 0⤋
A = 1/2h (b+c)
sub for A
50 = 1/2h (b+c)
sub for h
50 = 1/2(4) (b+c)
sub for c
50 = 1/2(4)(b+11)
now solve....
50 = 2 (b+11) ---> note 1/2 * 4 = 4/2 = 2
50 = 2b + 22 ---> note 2(b+11) = 2*b + 2*11 --> 2b + 22
50 - 22 = 2b + 22 - 22
28 = 2b
28/2 = 2b/2
14 = b
Note: algebra, everything u do to the right u also have to do to the left when cancelling terms or any function for that matter....
2008-01-01 03:04:35 · answer #2 · answered by aloofnerd 3 · 1⤊ 0⤋
Just filling in the known values gives us this equation:
50=1/2*4*(b+11)
50=2*(b+11) --- (1/2*4=2)
50/2=(2*(b+11))/2 --- (divide both sides by 2 to open up the b+11)
25-11=b+11-11 --- (subtract 11 from both sides to isolate b on one side of the equation)
14=b
2008-01-01 04:34:04 · answer #3 · answered by kaygee63 1 · 0⤊ 0⤋
is "A" related to the area of a trapezoid? It clearly seems to be that.
Well, if A = (1/2)h( b + c )
then b = (2A - ch ) / h
b = (2A ÷ h) - c
Giving b values:
b = ( (2*50) ÷ 4 ) - 11
= ( 100 ÷ 4 ) - 11
= 25 - 11
= 14
2008-01-01 04:18:35 · answer #4 · answered by fraukka 3 · 0⤊ 0⤋
A = 1/2h (b+c)
2A = h(b+c)
2A/h = b+c
b = (2A / h) - c
= (2*50/4) - 11
= (100/4) - 11
= 25 - 11
= 14
the answer is (1) 14
2008-01-01 05:24:57 · answer #5 · answered by Natali 2 · 0⤊ 0⤋
start with 2A =h(b+c) then go wrong when you treat h(b+c) as equivalent to ( a mental slip-up,but oh how costly..) hb + c where you have ignored - not even NOTICED! that glaring violation of the distributive property in the system (which I , God, hath decreeds to be so..) and then try to send 'c' across the other side as '-c-only', not '-c/h' ending up with an answer which was wrong...WRONG...not a nice word is it..?
2008-01-01 04:10:31 · answer #6 · answered by c0cky 5 · 0⤊ 0⤋
50=1/2 4(b+11)...50=2b+22...28=2b...14=b
2008-01-01 03:03:15 · answer #7 · answered by glenn t 7 · 1⤊ 0⤋