# Thread: Using Tangent: World Problem

1. ## Using Tangent: World Problem

Another problem I have is about a rectangles and adjacent sides. The answer is 53.01degrees and 36.99degrees. Here is the problem:

Two adjacent sides of a rectangle are 14.8cm and 11.9 cm. Find the angles which a diagonal of the rectangle makes with the sides.

Thank You For the Help!

2. Let the angle between the diagonal and the shorter side be x.

Then,
tan(x)=14.8/11.9

The other angle will be 90-x degrees.

3. Originally Posted by flutterby
Another problem I have is about a rectangles and adjacent sides. The answer is 53.01degrees and 36.99degrees. Here is the problem:

Two adjacent sides of a rectangle are 14.8cm and 11.9 cm. Find the angles which a diagonal of the rectangle makes with the sides.

Thank You For the Help!
According to my slide rule:

14.8/11.9 = 1.243697
&
Tan(51.198837degrees) = 1.243697465

If I were guessing, my guess is that the sides of the rectangle are 15.8 & 11.9

11.9/15.8 = 0.7532
arctan(0.7532) = 36.987 degrees

4. Can anyone please show me a diagram or explain how the diagram would look like? Thank you

5. Originally Posted by flutterby
Can anyone please show me a diagram or explain how the diagram would look like?
rectangle ... with diagonal

6. Originally Posted by malaygoel

The other angle will be 90-x = 36.99 degrees
can you please explain me this part!? why do I use 90 and how do I know I take this step! Thank You!

7. Originally Posted by flutterby
can you please explain me this part!? why do I use 90 and how do I know I take this step! Thank You!

Every right triangle has a 90 degree angle in it. The angles in any triangle add up to be 180 degrees. Therefore, in a right triangle with angles a,b, and c, where c is the right angle (90degrees), we have a+b+90=180. If we subract 90 from both sides we have a+b=90. if we had one of these angles (a or b) we could solve for the other one.

$90=a+b$

Subtract

$90-a=b$.

8. Originally Posted by flutterby
Another problem I have is about a rectangles and adjacent sides. The answer is 53.01degrees and 36.99degrees. Here is the problem:

Two adjacent sides of a rectangle are 14.8cm and 11.9 cm. Find the angles which a diagonal of the rectangle makes with the sides.

Thank You For the Help!
This should help. I forgot to put angle1 inside the parantheses. It should say tan(angle 1)=o/a. Dont forget that o=opposite side of the angle, and a=adjacent side of the angle.

9. Thank You I get it now, the only problem is that my calculator won't come up with the answer of 53.01. I plug in 14.8/11.9 and I get 1.2435... and then I find the inverse of tangent which gives me 51.19.

10. Originally Posted by flutterby
Thank You I get it now, the only problem is that my calculator won't come up with the answer of 53.01. I plug in 14.8/11.9 and I get 1.2435... and then I find the inverse of tangent which gives me 51.19.