Difference between revisions of "Activities- Quadratic equations problems"
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| Line 9: | Line 9: | ||
216=x2+6x<br> | 216=x2+6x<br> | ||
x2 +6x -216=0<br> | x2 +6x -216=0<br> | ||
| − | Substitution: x 2 +18x-12x -216=0 | + | Substitution: x 2 +18x-12x -216=0<br> |
| + | Simplification: x(x+18)-12(x+18)=0<br> | ||
| + | (x+18)( x-12)=0<br> | ||
| + | (x+18)=0 (x-12)=0<br> | ||
| + | x=-18, x=12<br>. | ||
| + | # Base=12cm, <br> Altitude=x+6 | ||
| + | =12+6=18cm.<br> | ||
| + | '''Prior Knowledge''' -<br> | ||
| + | *Methods of solving the Eqn<br> | ||
| + | *Factorisation<br> | ||
| + | *Using Formula<br> | ||
| + | *Using Graph<br> | ||
Revision as of 21:08, 12 July 2014
Ex.no.9.11 /problem no.9
The altitude of a triangle is 6cm greter than its base. If its area is 108cmsq .Find its base.
Statement: Solving problem based on quadratic equations.
- Interpretation of the problem:
* Converting data in to eqn.
*Knowledge about area of a triangle.
*knowledge of the formula of area of triangle.
*Methods of finding the roots of the eqn.
*Methods of finding the roots of the - Different approches to solve the problem:
*Factorisation - Using formula
- using graph
- Concept used:Forming the eqn. 216=x(x+6)
216=x2+6x
x2 +6x -216=0
Substitution: x 2 +18x-12x -216=0
Simplification: x(x+18)-12(x+18)=0
(x+18)( x-12)=0
(x+18)=0 (x-12)=0
x=-18, x=12
.
- Base=12cm,
Altitude=x+6
=12+6=18cm.
Prior Knowledge -
- Methods of solving the Eqn
- Factorisation
- Using Formula
- Using Graph