The area of a trapezoid is found with the formula A=1/2(b1+b2)h

.

A trapezoidal banner has an area of 120 m² and a height of 10 m. Base 1 (b1)
is 16 m shorter than base 2 (b2)
. What are the lengths of the two bases? Let b represent the length of base 1.

1 answer

To find the lengths of the two bases of the trapezoidal banner, we can start by using the formula for the area of a trapezoid:

\[ A = \frac{1}{2}(b_1 + b_2)h \]

We are given the area \( A = 120 , \text{m}^2 \) and the height \( h = 10 , \text{m} \). We can plug these values into the formula:

\[ 120 = \frac{1}{2}(b_1 + b_2) \cdot 10 \]

This simplifies to:

\[ 120 = 5(b_1 + b_2) \]

Now, divide both sides by 5:

\[ b_1 + b_2 = 24 \quad (1) \]

Next, we know that base 1 \( b_1 \) is 16 m shorter than base 2 \( b_2 \). We can express this relationship as:

\[ b_1 = b_2 - 16 \quad (2) \]

Now, we can substitute equation (2) into equation (1):

\[ (b_2 - 16) + b_2 = 24 \]

Combine like terms:

\[ 2b_2 - 16 = 24 \]

Add 16 to both sides:

\[ 2b_2 = 40 \]

Now, divide by 2:

\[ b_2 = 20 \quad (base , 2) \]

Now, we can find \( b_1 \) using equation (2):

\[ b_1 = b_2 - 16 = 20 - 16 = 4 \quad (base , 1) \]

Thus, the lengths of the two bases are:

  • Base 1 (\( b_1 \)) = 4 m
  • Base 2 (\( b_2 \)) = 20 m