find altitude to side of parallelogram, side of rt. triangle

[daniellagirl89]

48: A parallelogram of area 78 square units has one side of length 12. Find the length of an altitude to that side.

51: For right triangle ACB with right angle C, if m Ang A = 45o and BC = 3, what is the length of AC?

 

[pka]

Here is part of one.
\(\displaystyle \L A = h\frac{{a + b}}{2}\quad \Rightarrow \quad 150 = \left( {12} \right)\frac{{(18) + b}}{2}\)

 

[Denis]

In #51: what is measure of angle B?

If you don't know the answer, you need more help than you can get here...

 

[calchere]

What work have you done, or what part are you having trouble on?
Here is a bit of help.

48: A parallelogram of area 78 square units has one side of length 12. Find the length of an altitude to that side.

The area of a prallelogram is:

\(\displaystyle \H\
A = b*h\)

51: For right triangle ACB with right angle C, if m Ang A = 45o and BC = 3, what is the length of AC?

All the angles of a triangle add up to be 180 degrees: