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median am of triangle abc is half the length of ac and makes an angle of 32 degrees with side ac. find the measure of angle bac in degrees

User Jzd
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1 Answer

5 votes

Let's start by drawing a diagram:

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B

/ \

/ \

m / \ n

/ \

/_ _ _ _ _\

A c C

We know that the median m is half the length of ac, so we can label ac as 2m.

We also know that the median m makes an angle of 32 degrees with side ac. Since the median m also bisects bc, we know that angles Cbm and Abm are congruent, so each must measure (180 - 32)/2 = 74 degrees.

Now we can use the fact that the angles of a triangle add up to 180 degrees to solve for angle bac:

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angle BAC = 180 - angle ABC - angle ACB

We can find angle ABC as follows:

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angle ABC = angle ABm + angle Cbm

Since Abm is a right angle and Cbm is 74 degrees, we have:

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angle ABC = 90 + 74 = 164

Similarly, we can find angle ACB as follows:

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angle ACB = angle ACm + angle CBm

Since ACm is a right angle and CBm is 74 degrees, we have:

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angle ACB = 90 + 74 = 164

Now we can plug in these values to find angle BAC:

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angle BAC = 180 - angle ABC - angle ACB

= 180 - 164 - 164

= 180 - 328

= -148

This answer doesn't make sense since angles are measured between 0 and 180 degrees. So we made a mistake somewhere. Let's check our work.

We found that ABC is 164 degrees, which means that angle BCA must be (180 - 164)/2 = 8 degrees. But this is a problem since angle BCA should be greater than angle ACB, which we found to be 164 degrees. So we made a mistake when we assumed that angles Cbm and Abm are congruent.

Let's try again:

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B

/ \

/ \

m / \ n

/ \

/_ _ _ _ _\

A c C

Since the median m bisects bc, we know that angles Cbm and Abn are congruent, so each must measure (180 - 32)/2 = 74 degrees.

Now we can find angle BAC as follows:

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angle BAC = angle BAm + angle CAM

Since BAm and CAM are congruent, we have:

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angle BAC = 2 * angle BAm

We know that angle BAm is equal to 90 - 32/2 = 74 degrees, so:

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angle BAC = 2 * 74

= 148

Therefore, the measure of angle bac is 148 degrees.

User TheIrishGuy
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7.2k points