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uhfinn:

An isosceles trapezoid has base angles of 45° and bases of lengths 8 and 14. The area of the trapezoid is

Shadow:

hi

uhfinn:

hey sup shadow

Shadow:

Let me draw this bad boy

Shadow:

|dw:1576599657345:dw|

Shadow:

The area of a trapezoid is found using the following formula: \[A_{t} = \frac{ a+ b }{ 2 }h\]

Shadow:

a is 8, b is 14

Shadow:

We need h, or the height of the trapezoid

Shadow:

Are you familiar with trigonometry, or Sin/Cos/Tan?

uhfinn:

not at all

Shadow:

Oi

Shadow:

Well it's a way of dealing with triangles. Pretty sure it's the easiest way to solve this, so I don't know why you'd get this problem without having learned it xd

Shadow:

|dw:1576600010290:dw|

Shadow:

We draw a line and see our triangle take shape. Notice that the height of the triangle is the height of the trapezoid.

uhfinn:

33 sq. units 33√2 sq. units 72 sq. units da answer choices i forgot to put earlier

Shadow:

There's an acronym for Sin/Cos/Tan that goes, SOH CAH TOA It stands for Sine = Opposite/Hypotenuse Cosine = Adjacent/Hypotenuse Tangent = Opposite/Adjacent

Shadow:

We'll use tan to look at the height of the triangle (opposite to the 45 degree angle), and the base of the triangle (adjacent to the 45).

Shadow:

We find the base by subtracting 8 from 14 Getting this area ->|dw:1576600227577:dw|

Shadow:

\[\tan 45 = \frac{ x }{ 6 }\]

Shadow:

Or we could use big brain and realize that an isosceles triangle is a triangle with two equal sides. Lol

Shadow:

So the base of the triangle is the same length as the height of the triangle. You don't need trig identities.

Shadow:

That's just not graphically depicted in what I drew. Sorry, no sleeps :P

Shadow:

|dw:1576600403123:dw|

Shadow:

\(\color{#0cbb34}{\text{Originally Posted by}}\) @Shadow The area of a trapezoid is found using the following formula: \[A_{t} = \frac{ a+ b }{ 2 }h\] \(\color{#0cbb34}{\text{End of Quote}}\) a is 8, b is 14, h is 6

Shadow:

Input and you get your answer.

Shadow:

@uhfinn you followed all that?

Shadow:

Hmm actually, that doesn't come out right.

uhfinn:

yea i ddidnt get da right answer

Shadow:

I got it don't worry

Shadow:

So I forgot that there's two triangles in our trapezoid lol

Shadow:

|dw:1576600840058:dw|

Shadow:

This is why for geometry problems, it's helpful to draw it all out.

Shadow:

So to get the base of one side triangle of a trapezoid, do (bottom - top)/2

Shadow:

Input that new height and you should be good

uhfinn:

ok got it thank you shadow ur so cool and awesome ur awesome thanks

Shadow:

np

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