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# finding unknown angles

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a diagonal cut of length 2.85m is to be made on a rectangular wooden slab from one corner to the other. the front of the slab measures 1.94 m. calculate the angle with the front edge at which the carpenter needs to begin the cut. round the answer to one decimal place.

Guest Aug 8, 2017
edited by Guest  Aug 8, 2017

#1
+5907
+3

We have a right triangle where  one leg = 1.94 m  and the  hypotenuse = 2.85 m  .

And...we can find the measure of angle  a  using the cosine.

cos a  =  adjacent / hypotenuse

cos a  =  1.94 / 2.85

Take the arccosine of both sides.

a  =  arccos( 1.94 / 2.85 )

Put this into a calculator to get that.....

a  ≈  47.1°

hectictar  Aug 8, 2017
Sort:

#1
+5907
+3

We have a right triangle where  one leg = 1.94 m  and the  hypotenuse = 2.85 m  .

And...we can find the measure of angle  a  using the cosine.

cos a  =  adjacent / hypotenuse

cos a  =  1.94 / 2.85

Take the arccosine of both sides.

a  =  arccos( 1.94 / 2.85 )

Put this into a calculator to get that.....

a  ≈  47.1°

hectictar  Aug 8, 2017

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