Posted by sarah on .
Compute the area of a triangle with a base of 15 cm and an altitude of 10.5 in.
Area (to the nearest tenth) = cm2
I plugged everything into the area formula which is A = (1/2)bh .
A=.5x15x10.5= I got 78.75 rounded 78.8.
The computer keeps saying I am wrong. What am I doing wrong?

Math 
Steve,
Looks good to me. Computer may have wrong answer. Better check with your instructor. Have you tried entering 78.7 just in case they rounded wrong?

Math 
PsyDAG,
If your data are correct, I don't see anything you are doing wrong.

Math 
Steve,
Aha! Note that the area is
(1/2)(15 cm)(10.5 in)
= (1/2)(15 cm)(26.67 cm)
= 200.0 cm^2
Gotta watch those units!
Not a trick question, but ... 
Math 
sarah,
How did you get 26.67?

Math 
Steve,
you gotta know that
1 in = 2.54 cm 
Math 
sarah,
Omg Thank you !! I now know how to solve this type of problem the correct way ! Thank you so much !

Math 
PsyDAG,
Sorry that I missed the difference in units.
10.5 inches = 26.67 cm.