



 
Hi Bailey. The area of a triangle is (1/2) times the base times the height. Let b = the base length, h = the height, and A = the area. Then
You said "the length of the base...is 1cm less than 5 times the height...". So:
Therefore you can substitute this expression for b into the area equation. Thus A = (1/2) b h becomes:
You said "the area...is 21 square cm". So A = 21.
This is a quadratic equation. When we put it in standard form we get:
Now can you solve for the height (h) using factoring or completion of the square? Remember that the height of a triangle must be a positive number. Then you can use that to find b using b = 5h  1. Write us back if you are still stuck (tell us where you have trouble). Cheers,  


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