need help drawing diagram for "A retaining wall is leaning at an angle of 70° to the horizontal...."

[senakuny]

I just need help drawing diagram for this trig question!!! (answer not needed, just a diagram for this question!)

A retaining wall is leaning at an angle of 70° to the horizontal. A rigid support is to be placed 5.0 m from the base of the wall and it will be attached to the wall 2.5 m from its base. Determine the length of the support to the nearest tenth of a mere and measure of the angle between the support and the wall to the nearest degree.

 

[skeeter]

 

[Dr.Peterson]

A retaining wall is leaning at an angle of 70° to the horizontal. A rigid support is to be placed 5.0 m from the base of the wall and it will be attached to the wall 2.5 m from its base. Determine the length of the support to the nearest tenth of a mere and measure of the angle between the support and the wall to the nearest degree.

The angle between the support and the wall would probably be measured where I show it, though someone could disagree. The latter would be more likely if the angle shown were not, as it appears to be, acute. (That's why I wanted to make a more accurate drawing.)

 

[Ahatmose]

I think this might be correct.

 

[Ahatmose]

Here is the rest of the story.

Cheers

 

[Dr.Peterson]

I think this might be correct.

View attachment 35314

You didn't show the details of your work (how you got 2.35 and 4.125, presumably using the sine and cosine of 70), but the results are correct. (There is a very small error introduced by using the rounded value 2.35.)

You could instead have used the Law of Cosines.

 

[Ahatmose]

Er .... I put rounded (rnd) down as I have been chastised other places for too many decimals. And yes I used the law of sine of 70 degrees = 0.93969262078590838405410927732473 x 2.5 = 2.3492315519647709601352731933118

Then used Pythagoras to get the third side

 

[The Highlander]

Er .... I put rounded (rnd) down as I have been chastised other places for too many decimals. And yes I used the law of sine of 70 degrees = 0.93969262078590838405410927732473 x 2.5 = 2.3492315519647709601352731933118

Then used Pythagoras to get the third side

Yes, quoting lengthy decimal fractions in posts (like “0.93969262078590838405410927732473 x 2.5 = 2.3492315519647709601352731933118”) is unsightly but you should always (wherever possible) leave any rounding to your final result.

Storing intermediate results in your calculator’s memory should preserve their accuracy but it’s fine to 'quote' them to a few decimal places in the text of your posts (or on diagrams).

 

[senakuny]

You didn't show the details of your work (how you got 2.35 and 4.125, presumably using the sine and cosine of 70), but the results are correct. (There is a very small error introduced by using the rounded value 2.35.)

You could instead have used the Law of Cosines.

I've decided to use Cosine and Sine Law! Thanks for you help

 

[Dr.Peterson]

Er .... I put rounded (rnd) down as I have been chastised other places for too many decimals. And yes I used the law of sine of 70 degrees = 0.93969262078590838405410927732473 x 2.5 = 2.3492315519647709601352731933118

Then used Pythagoras to get the third side

I previously missed the fact that you are not the OP. Rules of the site call for not giving a complete answer until the OP has had time to use whatever hints have been given. (It's not quite stated explicitly, but when it says "We don't do your homework; we help you do it", the "we" means anyone who replies, including you!)

As for using too many decimals, as Highlander said, that can be a bad thing in a final answer, but it is important not to round (too much) in your intermediate work.