Question

the diagram shows a triangle.
what is the value of ( a )?
( a = square^circ )

Explanation:

Step1: Sum angles to 180°

$$(2a+9) + (4a-3) + 30 = 180$$

Step2: Simplify left side

$$6a + 36 = 180$$

Step3: Isolate term with $a$

$$6a = 180 - 36$$
$$6a = 144$$

Step4: Solve for $a$

$$a = \frac{144}{6}$$

Answer:

$24$