Hey there!
Things to remember:
- <em>The total angle in a triangle is 180°</em>
- <em>The base angles in an isosceles triangle are equal. </em>
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(6) One of the base angle is (9x-25)
Hence, the angles are:
(9x-25) , (9x-25) and 104
Their sum is 180.
Hence,
... 9x-25+9x-25+104=180
... 18x-50+104=180
... 18x+54=180
... 18x=180-54
... 18x=126
... x=126/18
... x=7
<em>Hence, the value of the variable is '7'. </em>
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(10) In this triangle, the base angle is 20, vertex angle is 11x-65
Hence,
The angles are (11x-65),29 and 29
Their sum is 180°
Hence,
...11x-65+29+29=180
...11x-65+58=180
...11x-7=180
...11x=180+7
...11x=187
...x=187/11
...x=17
<em>Hence, the value of the variable is 17. </em>
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Hope my answer helps!
