Question

what is the area? 10 km 9 km square kilometers

Explanation:

Step1: Recall triangle - area formula

The formula for the area of a triangle is $A=\frac{1}{2}bh$, where $b$ is the base and $h$ is the height.

Step2: Identify base and height

From the figure, the base $b = 9$ km and the height $h=10$ km.

Step3: Calculate the area

Substitute $b = 9$ and $h = 10$ into the formula: $A=\frac{1}{2}\times9\times10=\frac{90}{2}=45$ square kilometers.

Answer:

45