Question

Find the missing part.

Answer 1

Answer:

The answer is $a = \frac{15}{4}$

Step-by-step explanation:

We have to:

$cos(\theta) = \frac{adjacent\ side}{hypotenuse}$

So, if we take the 60 degree angle of the smallest triangle, we have to:

$cos(60) = \frac{a}{x}$

We do not know x. But if we take the sine of the angle of 30 degrees and the main triangle we have:

$sin(30) = \frac{x}{15}\\\\x =\frac{15}{2}$

Then:

$cos(60) = \frac{a}{\frac{15}{2}}$

$a = cos(60)\frac{15}{2}$

$a = \frac{15}{4}$