Question: Find the value of Xº if <ADC = 71°
Answer:
15
Explanation:
Given:
<ADC = 71°
<ADB = (x + 7)°
<BDC = (2x + 19)°
Required:
Value of x
Solution:
<ADB + <BDC = <ADC
(x + 7)° + (2x + 19)° = 71°
x + 7 + 2x + 19 = 71
x + 2x + 7 + 19 = 71
3x + 26 = 71
Subtract 26 from both sides
3x + 26 - 26 = 71 - 26
3x = 45
Divide both sides by 3 to make x the subject of formula
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
The value of x is 15.