Hi there!
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I believe your answer is:
[tex]h =\frac{A}{b}[/tex]
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Here’s why:
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[tex]\boxed{\text{Solving for 'h'...}}\\\\A=bh\\----------\\\rightarrow bh = A\\\\\rightarrow \frac{bh=A}{b}\\\\\rightarrow \boxed{h=\frac{A}{b}}[/tex]
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Hope this helps you. I apologize if it’s incorrect.