Determine the intensity of electromagnetic waves

Solve the all parts of following question given below:

Question: The sun emits electromagnetic waves with a power of 4.0 x 1026 Watts.

Part I: Determine the intensity of electromagnetic waves from the sun just outside the atmospheres of Venus.

Part II: Determine the intensity of electromagnetic waves from the sun just outside the atmospheres of the earth.

Part III: Determine the intensity of electromagnetic waves from the sun just outside the atmospheres of Mars.

Thanks so much for your help, please provide each step and equations and numbers you used in the above question.