$\"\"$

From the diagram, one sides of a triangle is 6.3 yd.

The other two sides are equal so we can assume as x and x.

Perimeter P = 22.5 yd.

To Find: x.

$\"\"$ $\"\"$ (Formula for perimeter)

$\"\"$ (Substitute: Perimeter P = 22.5 yd)

$\"\"$ (Add: $\"\"$ )

$\"\"$ (Subtarct 6.3 from each side)

$\"\"$ (Apply addiitve inverse propetry: $\"\"$ )

$\"\"$ (Apply addiitve identity propetry: $\"\"$ )

$\"\"$ (Subtarct: $\"\"$ )

$\"\"$

$\"\"$ (Divide each side by 2)

$\"\"$ (Cancel common terms)

$\"\"$ (Divide: $\"\"$ )

The unknown side lengths of the triangle is 8.1yd and 8.1yd. $\"\"$

The unknown side lengths of the triangle is 8.1yd and 8.1yd.