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# Triangle Area edited

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Find the area of an isosceles triangle with two sides being 1 and an angle A being 30 degrees.

Aug 9, 2017

#4
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There is a formula to find the area of a triangle for this exact situation. I will use a picture to illustrate it:

In the diagram above, if we know the lengths of 2 sides of a triangle and the measure of the included angle, then the area of the triangle can be found using the formula of $$A_\triangle=\frac{1}{2}ab\sin C$$. Now, let's apply the formula!

 $$A_\triangle=\frac{1}{2}ab\sin C$$ Plug in the the side lengths as a and b (order is immaterial) and the measure of the included angle as C. $$A_\triangle=\frac{1}{2}(1)(1)\sin 30^{\circ}$$ Let's simplify the sin of 30 degrees. You may already be aware that$$\sin 30^{\circ}=0.5$$. $$A_\triangle=\frac{1}{2}(1)(1)(0.5)$$ If you multiply a number by 1, the number is itself. $$A_\triangle=\frac{1}{2}(0.5)$$ (1/2)*0.5=1/4, or 0.25. $$A_\triangle=\frac{1}{4}units^2=0.25units^2$$
Aug 9, 2017

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http://web2.0calc.com/questions/triangle-area_3

Aug 9, 2017
#2
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I'm mildly glad that this question was answered previously because reference to $$\angle A$$ is still ambiguous; $$\angle A$$  can refer to $$\angle CAD$$$$\angle CAB$$$$\angle BAD$$

If you want to reference an angle that has several common vertices, it is impossible to determine which angle one is referring to. Solve the problem by using 3 letters as opposed to 1. Can you please clarify which angle is indeed $$\angle A$$

Aug 9, 2017
#3
+166
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angle CAB

Aug 9, 2017
#4
+2298
+1

There is a formula to find the area of a triangle for this exact situation. I will use a picture to illustrate it:

In the diagram above, if we know the lengths of 2 sides of a triangle and the measure of the included angle, then the area of the triangle can be found using the formula of $$A_\triangle=\frac{1}{2}ab\sin C$$. Now, let's apply the formula!

 $$A_\triangle=\frac{1}{2}ab\sin C$$ Plug in the the side lengths as a and b (order is immaterial) and the measure of the included angle as C. $$A_\triangle=\frac{1}{2}(1)(1)\sin 30^{\circ}$$ Let's simplify the sin of 30 degrees. You may already be aware that$$\sin 30^{\circ}=0.5$$. $$A_\triangle=\frac{1}{2}(1)(1)(0.5)$$ If you multiply a number by 1, the number is itself. $$A_\triangle=\frac{1}{2}(0.5)$$ (1/2)*0.5=1/4, or 0.25. $$A_\triangle=\frac{1}{4}units^2=0.25units^2$$
TheXSquaredFactor Aug 9, 2017