Estimating the sun's diameter with a meter stick and the Earth's radius from sunset timing

[Indigo Prophercy]

I got these 2 questions for homework and i can't figure them out.

Number 1 is With only a metre-stick, a piece of paper and the knowledge that the sun is 1.50 x 10^11m from the earth, how can one estimate the suns diameter.

Number 2 is You can watch the sun set and disappear over a calm ocean while you lie on the beach, then once again if u stand up. Determine an approximate value of the Earth's radius. Measuring the time between the 2 sun sets.

If anyone can help i would be so thankful!

 

[Tide]

You're supposed to show some of your work before anyone can help.