Cost Basis of stock after acquistion

Trying to determine the cost basis of a stock after it has been acquired.  I owned ~4700 shares in a company with a cost basis of ~42K.  The company was purchased for stock and cash.  I received ~5300 shares and ~87K in cash.

So do I pay capital gains of $45K on the return of capital (87 - 42)?

What then is the cost basis for 5300 shares I received?