Calculate Triangle Area: Right Triangle with Height 5.5 and Base 7.8

To solve this problem, we'll follow these steps:

• Step 1: Identify the given information:
• The base of the triangle is $7.8$ units.
• The height of the triangle is $5.5$ units.
• Step 2: Apply the formula for the area of a right triangle:

The formula for the area of a triangle is:

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

Step 3: Perform the necessary calculations:

Substitute the values we have:

$\text{Area} = \frac{1}{2} \times 7.8 \times 5.5$

Calculating further:

$\text{Area} = \frac{1}{2} \times 42.9$ $\text{Area} = 21.45$

Therefore, the area of the triangle is $21.45$ square units.

This matches with choice 4 provided: 21.45.