A triangle with an area of 224 square centimeters has a height that is 8 more than 6 times its base. Find the base and height, in centimeters, of the triangle.

1 answer

To solve the problem, we need to use the formula for the area of a triangle:

\[ \text{Area} = \frac{1}{2} \times \text{base} \times \text{height} \]

Given that the area of the triangle is \(224\) square centimeters, we can set up the equation:

\[ \frac{1}{2} \times b \times h = 224 \]

Multiplying both sides by \(2\), we get:

\[ b \times h = 448 \]

Next, we are told that the height \(h\) is 8 more than 6 times the base \(b\). We can express this relationship as:

\[ h = 6b + 8 \]

Now, we can substitute the expression for \(h\) into the area equation:

\[ b \times (6b + 8) = 448 \]

This expands to:

\[ 6b^2 + 8b = 448 \]

To turn it into a standard quadratic equation, we'll subtract \(448\) from both sides:

\[ 6b^2 + 8b - 448 = 0 \]

Now, we can simplify this equation by dividing everything by \(2\):

\[ 3b^2 + 4b - 224 = 0 \]

Next, we will solve this quadratic equation using the quadratic formula:

\[ b = \frac{-B \pm \sqrt{B^2 - 4AC}}{2A} \]

In our equation, \(A = 3\), \(B = 4\), and \(C = -224\). First, we calculate the discriminant:

\[ B^2 - 4AC = 4^2 - 4 \times 3 \times (-224) = 16 + 2688 = 2704 \]

Now we find the square root of the discriminant:

\[ \sqrt{2704} = 52 \]

Now we can apply the quadratic formula:

\[ b = \frac{-4 \pm 52}{2 \times 3} = \frac{-4 \pm 52}{6} \]

This gives us two possible values for \(b\):

  1. When we use the positive root: \[ b = \frac{48}{6} = 8 \]

  2. When we use the negative root: \[ b = \frac{-56}{6} = -\frac{28}{3} \quad (\text{not a valid solution as base cannot be negative}) \]

Thus, we have:

\[ b = 8 \text{ cm} \]

Now we can find \(h\) using the relationship \(h = 6b + 8\):

\[ h = 6(8) + 8 = 48 + 8 = 56 \text{ cm} \]

Finally, the base and height of the triangle are:

\[ \text{Base} = 8 \text{ cm}, \quad \text{Height} = 56 \text{ cm} \]

Thus, the solution is:

\[ \boxed{8} \text{ cm for the base and } \boxed{56} \text{ cm for the height.} \]