trapezoids!!!?
my daughter has a math problem for homework that neither of us can figure out! if anyone could help us solve this, it would be very much appreciated!!
Use the formula A = 1/2h(a + b) to find the length of the missing base for a trapezoid with A = 140 square cm, a = 9 cm, and h = 8 cm.
thanks again!
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A=1/2h(a+b)
140=1/2*8(9+b)
140=36+4b
4b=104
b=26cm..is this right..?
This is a simple algebra question. Plug in the known values you have. Then, solve for b. In this case, sense you have the equation, you don't even need to think about the trapezoid itself. This is solved purely with algebra.
A = 1/2h(a+b)
140 = 1/2(8)(9+b)
140 = 4(9+b)
140 = 36 + 4b
104 = 4b
26 = b
b = 26
140 = ½ x 8 (9+ b)
140 = 4 (9+b)
35 = 9+b
26 = b
the missing base would be "b" in the formula
you could solve for "b"
A=1/2h(a+b)
2A=h(a+b)
2A/h=a+b
2A/h-a=b
substitute values
2(140)/8 - 9 =b
b=26