word problem: Base times height

[silverdragon316]

The base of a triangle is 3ft less than the height. The area is 27 ft^2. Find the height and the base. A=1/2bh:

h(h-3)/2=27
----2h-3=27
------2
(2) 2h-3=27(2)
------2
4h-6=54
---+6=+6

----4h=60
-----4---4

h=15
Since the height is 15ft the base has to be 12 because it is -3 less than the height. Am I correct.

 

[Denis]

The base of a triangle is 3ft less than the height. The area is 27 ft^2. Find the height and the base. A=1/2bh.
How do you go about setting this equation up?

Betya that h(h - 3) / 2 = 27 should work...try it

 

[silverdragon316]

The base of a triangle is 3ft less than the height. The area is 27 ft^2. Find the height and the base. A=1/2bh.

How do you go about setting this equation up?

I am still a little confussed on what to do with what you told me. :?

 

[jonboy]

I am still a little confussed on what to do with what you told me. :?

" h(h - 3) / 2 = 27 "

Solve for h. Determine which is the base and height and you got your answer.

The base of a triangle is 3ft less than the height. The area is 27 ft^2. Find the height and the base. A=1/2bh.

 

[stapel]

I am still a little confussed on what to do with what you told me.

You've drawn the triangle, right? And labelled the height line as "h"...? And created an expression, in terms of h, for the length of the base, and labelled the picture with that...? And then plugged the height variable, base expression, and area value into the "area" equation...?

Since apparently you didn't end up with what the tutor had expected, it would be helpful if you replied showing your work and reasoning. Thank you.

Eliz.

 

[silverdragon316]

The base of a triangle is 3ft less than the height. The area is 27 ft^2. Find the height and the base. A=1/2bh:

-------A=(1/2)bh
27ft^2=1/2*h(3ft)
54ft^2=(3ft)h
----18ft=h

Since the height is 18ft the base has to be 15 because it is -3 less than the height. Am I correct.

am I correct?

 

[stapel]

Please post replies as replies, not as stealth-edits of the original posts, thus confusing the correspondence (and correspondents). Thank you.

am I correct?

Only if the exercise was posted incorrectly to start with. The original language said that the base was three less than the height. In your set-up, rather than using variables and expressions as the tutors explained, you instead declared the base to have a length of 3, and then solved for the height.

Check your work: Is 3 three less than 18? If not, then your solution does not fit the posted exercise. Either follow the provided instructions to solve the posted exercise, or else reply with a correction of the exercise.

Thank you.

Eliz.

 

[silverdragon316]

The base of a triangle is 3ft less than the height. The area is 27 ft^2. Find the height and the base. A=1/2bh:

h(h-3)/2=27
----2h-3=27
------2
(2) 2h-3=27(2)
------2
4h-6=54
---+6=+6

----4h=60
-----4---4

h=15
Since the height is 15ft the base has to be 12 because it is -3 less than the height. Am I correct.

is this right?

 

[Denis]

Where were you during math classes, SD?

h(h - 3) = h^2 - 3h

So: (h^2 - 3h) / 2 = 27
h^2 - 3h = 54
h^2 - 3h - 54 = 0

If you can't finish that, you need classroom help.

 

[stapel]

The base of a triangle is 3ft less than the height. The area is 27 ft^2. Find the height and the base. A=1/2bh:

h(h-3)/2=27
----2h-3=27
------2
(2) 2h-3=27(2)
------2
4h-6=54
---+6=+6

----4h=60
-----4---4

h=15
Since the height is 15ft the base has to be 12 because it is -3 less than the height. Am I correct.

is this right?

This is your third version of your "original" post. Is this your final version, or are you going to change the question again later?

(It seems rather pointless for us to continue trying to "hit a moving target", especially one so badly formatted....)

Eliz.