Question

1. triangle abc has interior angle measures of 30° and 70°. a what is the measure of the 3rd interior angle? b is this an isosceles triangle? explain how you know.

Explanation:

Step1: Calculate the third - interior angle

The sum of interior angles of a triangle is \(180^{\circ}\). Let the third angle be \(x\). Then \(x + 30^{\circ}+70^{\circ}=180^{\circ}\).

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Step2: Determine if it is an isosceles triangle

An isosceles triangle has at least two equal - measure angles. The angles of the triangle are \(30^{\circ}\), \(70^{\circ}\), and \(80^{\circ}\). Since \(30
eq70
eq80\), there are no two equal - measure angles.

Answer:

a) \(80^{\circ}\)
b) No. Because an isosceles triangle has at least two equal - measure angles, and the angles of this triangle (\(30^{\circ}\), \(70^{\circ}\), \(80^{\circ}\)) are all different.