Question

label (on the diagram) all angles in the diagram. 8)

Explanation:

Step1: Use the sum of angles in a triangle property

In a triangle, the sum of interior angles is \(180^{\circ}\). For the left - hand triangle with two \(70^{\circ}\) angles, the third angle is \(180-(70 + 70)=40^{\circ}\).

Step2: Use the right - angle property

Since there is a right - angle (\(90^{\circ}\)) in the figure, and we know one angle is \(25^{\circ}\) and the angle adjacent to the \(40^{\circ}\) angle (from step 1) in the right - hand part of the figure. Let the unknown angle be \(x\). We know that \(40 + x+25=90\) (because the sum of angles in the right - angled part of the figure).

Step3: Solve for the unknown angle

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Answer:

The unknown angle is \(25^{\circ}\)