Question

problem 21: (first taught in lesson 30) find x in terms of y. 80° x° y°

Explanation:

Step1: Use the triangle angle - sum theorem

The sum of the interior angles of a triangle is \(180^{\circ}\). So, \(x + y+80 = 180\).

Step2: Solve for \(x\)

Subtract \(y + 80\) from both sides of the equation \(x + y+80 = 180\).
\(x=180-(y + 80)\).
Simplify the right - hand side: \(x = 100 - y\).

Answer:

\(x = 100 - y\)