Question

Solve x for this triangle diagram!

Answer 1

x = 40

Explanation:

Angles on a straight line sum to 180°.

Therefore, from inspection of the given diagram:

`\implies x^(\circ) + 100^(\circ) + x^(\circ)=180^(\circ)`

`\implies 2x^(\circ) + 100^(\circ)=180^(\circ)`

`\implies 2x+100=180`

`\implies 2x+100-100=180-100`

`\implies 2x=80`

`\implies 2x / 2=80/ 2`

`\implies x=40`

Answer 2

• 40°

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The three given angles add up to 180°:

• 100 + 2x = 180
• 2x = 180 - 100
• 2x = 80
• x = 80/2
• x = 40