Answer:
x = 20
y = 20
Explanation:
Remark
This is a proportional question. One triangle is inside the other. I've used the larger to the smaller.
Equation
x/16 = 15 / 12
Solution for x
12x = 15 * 16
Divide by 12
x = 15 * (16/12)
x = 15 * (4/3)
x = 60 / 3
x = 20
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Solution for y
(y + 5) / y = 15/12 Reduce the right
(y + 5) / y = 5/4 Cross Multiply
4(y+5) = 5y Remove the brackets
4y + 20 = 5y Subtract 4y from both sides
20 = 5y - 4y
20 = y