Let the actual heights of Lisa, Ian and Jim be L, I and J.
i) "Lisa is 4 centimeters taller than her friend Ian." means: L=4+I
ii) "Ian is 8 centimeters taller than Jim." means: I=8+J, thus J=I-8
so the heights of Lisa, Ian and Jim are 4+I, I and I-8, respectively.
Since their heights increase by 2 cm, in 4 months, their heights increase 2 cm*4 = 8 cm.
Thus, after 4 months the heights of Lisa, Ian and Jim become:
4+I +8, I+8 and I-8+8 that is I + 12, I+8, I.
In 4 months, "the sum of Ian's and Jim's heights will be 140 centimeters more than Lisa's height. " mean:
(I+8)+I=140+(I+12)
2I+8=152+I
I=152-8=144
This solution made use of writing all the ages in terms of Ians current age.
19). sin(a) = 35/37
cos(a) = 12/37
Third choice.
20).
tangent(20°) = 10/x
x = 10/tangent(20°) = 10/0.364 = 27.475
Rounded to the nearest tenth: x = 27.5
<span>-6x = 3x-54
-6x - 3x = -54
-9x = -54
9x = 54
x = 54/9
x = 6</span>
Answer:
26.46
Step-by-step explanation:
use a calculator it's not hard