## anonymous 4 years ago Area of trapezoid

1. anonymous

2. anonymous

I know the answer is D

3. anonymous

Its something with 45 30 90 or something that one angle on the left

4. saifoo.khan

$\frac12\times base \times \text{(s um of p arallel sides)}$

5. anonymous

you use the 1/2h (b1+b2)

6. saifoo.khan

Yes.

7. saifoo.khan

But we have to find the value of the line adjacent with 45*/

8. anonymous

Yeah how its something with 45 30 90 or something my teacher said i forgot

9. saifoo.khan

Use tan ratio to find it.

10. saifoo.khan

$\tan \theta = \frac{opp}{adj}$ $\tan 45 = \frac{7}{adj}$ $adj = 7$|dw:1330659614940:dw|

11. saifoo.khan

Now you have all the values, $\frac12 * 7 * (8+8+3+7)$Solve.:)

12. anonymous

ohh its 7 why do you use tan?

13. saifoo.khan

Because we have to choose either one of the three ratios.. If you feel confusion, try writing the 2 other ratios as well.. And try applying them. Later you will find that u can't use those here.

14. anonymous

oh alright thanks, got a big test tomorrow!

15. saifoo.khan

Best of luck. Believe me, i too used to get confused b/w which one to use.. then i found a shortcut. ;)