Question

第 $7, 8$ 和 $9$ 题与这些风筝有关。

为了宣传学校一年一度的风筝奥林匹克活动，Genevieve 为公告板展示制作了一个小风筝和一个大风筝。风筝形状如图。对于小风筝，Genevieve 在一英寸方格纸上画风筝。对于大风筝，她将整个方格的高度和宽度都扩大为原来的三倍。

小风筝的面积是多少平方英寸？

Problems $7, 8,$ and $9$ are about these kites.

To promote her school’s annual Kite Olympics, Genevieve makes a small kite and a large kite for a bulletin board display. The kites look like the one in the diagram. For her small kite Genevieve draws the kite on a one-inch grid. For the large kite she triples both the height and width of the entire grid.

What is the number of square inches in the area of the small kite?

$21$

$22$

$23$

$24$

$25$

答案：A

知识点：筝形面积对角线

难度评级：900

解答：

风筝面积等于两条对角线的乘积除以 $2$ 。

因此小风筝面积为 $\dfrac{6 \cdot 7}{2} = \dfrac{42}{2} = 21.$

所以正确答案是 A。

Recall that the area of a kite is the product of its diagonals divided by $2.$

Therefore, the area of the small kite is $\dfrac{6 \cdot 7}{2} = \dfrac{42}{2} = 21.$

Thus, A is the correct answer.

2001 AMC 8 第 7 题

答案：A

难度评级：900

解答：

其他年份的第 7 题