Math Is Fun Forum

Spanky

Member

Registered: 2010-02-24

Posts: 62

Determining the base of a triangle

The base of a triangle is 2 ft longer than the height.  Determine the base if the area of this triangle is 24 ft^2.
A=1/2 b*h

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Determining the base of a triangle

Hi Spanky;

24 = ( h * (h+2) ) / 2

48 = h^2 + 2h

h^2 + 2h - 48 = 0

( h - 6 ) ( h + 8 ) = 0

h = 6 ft. so the base = 8 ft.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Spanky

Member

Registered: 2010-02-24

Posts: 62

Re: Determining the base of a triangle

Thanks Bobbym.  Can you just explain to me what happens with the dividing by 2? I see the distributing but i'm unsure what you do with the /2.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Determining the base of a triangle

Hi Spanky;

1)  24 = ( h * (h+2) ) / 2

2)  48 = h^2 + 2h

Look at step 1 you should see a divide by 2. What you do to get rid of it is to multiply both sides of the equation by 2

2* 24 = 2 * ( h * (h+2) ) / 2

The 2's cancel on the right and 2 times 24 is 48, That's how we get equation 2). Is that clearer?  Post back right here if I have not made it clear.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Spanky

Member

Registered: 2010-02-24

Posts: 62

Re: Determining the base of a triangle

That's clear!! Thank you very much!!!