Answer:
[tex]a = 145\ cm[/tex]
Step-by-step explanation:
Given
[tex]a + b + c = 445[/tex]
[tex]a = 45 + b[/tex]
[tex]b = \frac{1}{2}c[/tex]
Required
Determine the length of a
Solve for c in [tex]b = \frac{1}{2}c[/tex]
[tex]2 * b = \frac{1}{2}c * 2[/tex]
[tex]2b = c[/tex]
[tex]c = 2b[/tex]
Substitute [tex]c = 2b[/tex] and [tex]a = 45 + b[/tex] in [tex]a + b + c = 445[/tex]
[tex]a + b + c = 445[/tex]
[tex]45 + b + b + 2b = 445[/tex]
[tex]45 + 4b = 445[/tex]
Solve for 4b
[tex]4b = 445 - 45[/tex]
[tex]4b = 400[/tex]
Solve for b
[tex]b = 400/4[/tex]
[tex]b = 100[/tex]
Recall that: [tex]a = 45 + b[/tex]
[tex]a=45+100[/tex]
[tex]a = 145\ cm[/tex]