Question

dorothy’s bookmark is shown in the image below. what is the area of dorothy’s bookmark? 1 cm 9 cm 11 cm 5 cm the area of dorothy’s bookmark is square cm.

Explanation:

Step1: Divide the bookmark into a rectangle and a trapezoid

The bookmark can be divided into a rectangle with length \(9\) cm and width \(5 - 1=4\) cm, and a trapezoid with parallel sides \(9\) cm and \(11\) cm and height \(1\) cm.

Step2: Calculate the area of the rectangle

The area of a rectangle \(A_{1}=l\times w\), where \(l = 9\) cm and \(w=4\) cm. So \(A_{1}=9\times4 = 36\) \(cm^{2}\).

Step3: Calculate the area of the trapezoid

The area of a trapezoid \(A_{2}=\frac{(a + b)h}{2}\), where \(a = 9\) cm, \(b = 11\) cm and \(h = 1\) cm. So \(A_{2}=\frac{(9 + 11)\times1}{2}=\frac{20\times1}{2}=10\) \(cm^{2}\).

Step4: Calculate the total area

The total area \(A=A_{1}+A_{2}\). So \(A = 36+10=46\) \(cm^{2}\).

Answer:

\(46\)