Geometry? ?

i will give brainliest : )

me find the length of ec below, and explain thoroughly. you can round your final answer if you wish.

additional info:

de is parallel to ac.

angle c is 60°.

angle a and angle bde are both right angles.

triangle abc is similar to triangle dbe.

What is the number 321,000,000 in scientific notation? also what is the number? ?

Igure 1 and figure 2 are two congruent parallelograms drawn on a coordinate grid as shown below: 4 quadrant coordinate grid showing two parallelograms. figure 1 has vertices at negative 5, 2 and negative 3, 4 and negative 4, 7 and negative 6, 5. figure 2 has vertices at 5, negative 2 and 7, negative 4 and 6, negative 7 and 4, negative 5. which two transformations can map figure 1 onto figure 2? reflection across the y-axis, followed by reflection across x-axis reflection across the x-axis, followed by reflection across y-axis reflection across the x-axis, followed by translation 10 units right reflection across the y-axis, followed by translation 5 units down

What is the area of a triangle with a base of 7x and height of 8x expressed as a monomial? question 5 options: 1x 15x2 28x2 56x2