the height of a triangle is 7cm greater than the length of its base and its area is 15cm sq. Find the height.?

Question

this is what i have but i dont think its right
(n+7)(n)=15
does any one know an alternative way

Answer 1

The base is 3 and the hieght is 10.

Answer 2

to find the area u multiply 1/2 times the base, times the height.
substitute this into the equation and get:
1/2(x+7)(x) = 15
(x+7) is the height. x is the length of the base
multiply both sides by 2 to get rid of the 1/2
x(x+7) = 30
distributive property
x^2+7x = 30
then get everything on one side by subtracting 30 from both sides
x^2+7x-30
then simplify the polynomial (i think thats what its called) and get:
(x+10)(x-3)
then to solve for x, do each one separately.
so u have 2 equations:
x+10=0 and x-3=0
your 2 answers are either -10 or 3, and since you cannot have a negative measurement, it has to be 3.

so x = 3 so that means the base is 3 and the height is 10.

if u check it, 3 times 10 is 30 and then u multiply that by 1/2 to get 15 for the area!
also, the base is 3 and add 7 to get the height and u get 10.

i hope this helps!

Answer 3

Let base = x
So height = x+7
So A = x(x+7)/2 = 15
x^2 +7x =30
x^2+7x-30=0
(x+10)(x-3)=0
x-3 = 0
x=3
height = x+7 = 3 + 7 = 10

Answer 4

A = a million/2(BH) So 2a = bh one hundred twenty = x(x + 7) x² + 7x - one hundred twenty = 0 (x - 8)(x + 15) = 0 x = 8 = correct (The adverse root of -15 makes no experience the following) So base = 8 + 7 = 15 verify : A = a million/2 (bh) 60 = a million/2 (15)(8) 60 = a million/2 (one hundred twenty) 60 = 60

Answer 5

the reason it's wrong is because you're not dividing the n(n+7) by two....area of triangle is bh/2.....you were doing base times hight

so (n)(n+7)/2=15
n^2+7n=30
n^2+7n-30=0
(n-3)(n+7)=0
n=3,-7
reject -7 becuase it's negative
so n=3 and the base is 3 and the height is 10!!!

Answer 6

The base is represented as n.
n+7 is the height.
Formula for area of triangle:ab/2
So
(n+7)(n)/2=15
(n+7)(n)=30
n(squared)+7n-30=0
(n+10 ) (n-3)=0
n=3,-10
n+7= 10 or 0
The height cannot be zero so it must be 10cm.
It is OK if you don't understand quadratic equations.

Answer 7

n(n+7)=30
where n is length of base
Remember, half of bh=area of triangle

when you solve it you get
n^2+7n-30=0
(n+10)(n-3)=0
n=3, because -10 does not make sense

therefore, n=3, n+7=10
or the length of base is 3 cm and height is 10 cm

Answer 8

i dont know the answer, but the way i learned was 1-2 base x height.

Answer 9

no get a life